has decreased during the period from 2002 to 2004, principally due to the increase in earned premium and due to cost containment measures undertaken by management.
In Business Insurance and Personal Lines, the expense ratio is expected to decrease further in 2005, largely as a result of expected increases in earned premium.
In Specialty Commercial, the expense ratio is expected to increase slightly in 2005 due to changes in the business mix, most notably the Company’s decision in the fourth quarter of 2004 to exit the multi-peril crop insurance program which will eliminate significant expense reimbursements from the Specialty Commercial segment.
Policyholder dividend ratio: The policyholder dividend ratio is the ratio of policyholder dividends to earned premium.
Combined ratio: The combined ratio is the sum of the loss and loss adjustment expense ratio, the expense ratio and the policyholder dividend ratio.
This ratio is a relative measurement that describes the related cost of losses and expense for every $100 of earned premiums.
A combined ratio below 100.0 demonstrates underwriting profit; a combined ratio above 100.0 demonstrates underwriting losses.
The combined ratio has decreased from 2003 to 2004 primarily because of improvement in the expense ratio.
The combined ratio in 2005 could be significantly higher or lower than the 2004 combined ratio depending on the level of catastrophe losses, but will also be impacted by changes in pricing and an expected moderation in favorable loss cost trends.
Catastrophe ratio: The catastrophe ratio (a component of the loss and loss adjustment expense ratio) represents the ratio of catastrophe losses (net of reinsurance) to earned premiums.
A catastrophe is an event that causes $25 or more in industry insured property losses and affects a significant number of property and casualty policyholders and insurers.
By their nature, catastrophe losses vary dramatically from year to year.
Based on the mix and geographic dispersion of premium written and estimates derived from various catastrophe loss models, the Company’s expected catastrophe ratio over the long-term is 3.0 points.
Before considering the reduction in Ongoing Operation’s catastrophe reserves related to September 11 of $298 in 2004, the catastrophe ratio in 2004 was 5.3 points.
See “Risk Management Strategy” below for a discussion of the Company’s property catastrophe risk management program that serves to mitigate the Company’s net exposure to catastrophe losses.
Combined ratio before catastrophes and prior accident year development: The combined ratio before catastrophes and prior accident year development represents the combined ratio for the current accident year, excluding the impact of catastrophes.
The Company believes this ratio is an important measure of the trend in profitability since it removes the impact of volatile and unpredictable catastrophe losses and prior accident year reserve development.
Before considering catastrophes, the combined ratio related to current accident year business has improved from 2002 to 2004 principally due to earned pricing increases and favorable claim frequency.
Other Operations underwriting results: The Other Operations segment is responsible for managing operations of The Hartford that have discontinued writing new or renewal business as well as managing the claims related to asbestos and environmental exposures.
As such, neither earned premiums nor underwriting ratios are meaningful financial measures.
Instead, management believes that underwriting result is a more meaningful measure.
The net underwriting loss for 2002 through 2004 is primarily due to prior accident year loss development, including $2.6 billion of net asbestos reserve strengthening in 2003.
Reserve estimates within Other Operations, including estimates for asbestos and environmental claims, are inherently uncertain.
Refer to the Other Operations segment MD&A for further discussion of Other Operation's underwriting results.
Total Property & Casualty Investment Earnings
## Table 0 ##
The investment return, or yield, on Property & Casualty’s invested assets is an important element of the Company’s earnings since insurance products are priced with the assumption that premiums received can be invested for a period of time before loss and loss adjustment expenses are paid.
For longer tail lines, such as workers’ compensation and general liability, claims are paid over several years and, therefore, the premiums received for these lines of business can generate significant investment income.
HIM determines the appropriate allocation of investments by asset class and measures the investment yield performance for each asset class against market indices or other benchmarks.
Due to the emphasis on preservation of capital and the need to maintain sufficient liquidity to satisfy claim obligations, the vast majority of Property and Casualty’s invested assets have been held in fixed maturities, including, among other asset classes, corporate bonds, municipal bonds, government debt, short-term debt, mortgage-
HLIKK has four revolving credit facilities in support of operations.
Two of the credit facilities have no amounts drawn as of December 31, 2013 with borrowing limits of approximately ￥5 billion, or $48 each, and individually have expiration dates of January 5, 2015 and September 30, 2014.
In December 2013, HLIKK entered into two new revolving credit facility agreements with two Japanese banks in order to finance certain withholding taxes on mutual fund gains, that are subsequently credited when HLIKK files its’ income tax returns.
At December 31, 2013, HLIKK had drawn the total borrowing limits of ￥5 billion, or $48, and ￥20 billion, or $190 on these credit facilities.
The ￥5 billion credit facility accrues interest at a variable rate based on the one month Tokyo Interbank Offering Rate (TIBOR) plus 3 bps, which as of December 31, 2013 the interest rate was 15 bps, and the ￥20 billion credit facility accrues interest at a variable rate based on TIBOR plus 3 bps, or the actual cost of funding, which as of December 31, 2013 the interest rate was 20 bps.
Both of the credit facilities expire on September 30, 2014.
Derivative Commitments Certain of the Company’s derivative agreements contain provisions that are tied to the financial strength ratings of the individual legal entity that entered into the derivative agreement as set by nationally recognized statistical rating agencies.
If the legal entity’s financial strength were to fall below certain ratings, the counterparties to the derivative agreements could demand immediate and ongoing full collateralization and in certain instances demand immediate settlement of all outstanding derivative positions traded under each impacted bilateral agreement.
The settlement amount is determined by netting the derivative positions transacted under each agreement.
If the termination rights were to be exercised by the counterparties, it could impact the legal entity’s ability to conduct hedging activities by increasing the associated costs and decreasing the willingness of counterparties to transact with the legal entity.
The aggregate fair value of all derivative instruments with credit-risk-related contingent features that are in a net liability position as of December 31, 2013 was $1.2 billion.
Of this $1.2 billion the legal entities have posted collateral of $1.4 billion in the normal course of business.
In addition, the Company has posted collateral of $44 associated with a customized GMWB derivative.
Based on derivative market values as of December 31, 2013, a downgrade of one level below the current financial strength ratings by either Moody’s or S&P could require approximately an additional $12 to be posted as collateral.
Based on derivative market values as of December 31, 2013, a downgrade by either Moody’s or S&P of two levels below the legal entities’ current financial strength ratings could require approximately an additional $33 of assets to be posted as collateral.
These collateral amounts could change as derivative market values change, as a result of changes in our hedging activities or to the extent changes in contractual terms are negotiated.
The nature of the collateral that we would post, if required, would be primarily in the form of U. S.  Treasury bills, U. S.  Treasury notes and government agency securities.
As of December 31, 2013, the aggregate notional amount and fair value of derivative relationships that could be subject to immediate termination in the event of rating agency downgrades to either BBB+ or Baa1 was $536 and $(17), respectively.
Insurance Operations Current and expected patterns of claim frequency and severity or surrenders may change from period to period but continue to be within historical norms and, therefore, the Company’s insurance operations’ current liquidity position is considered to be sufficient to meet anticipated demands over the next twelve months, including any obligations related to the Company’s restructuring activities.
For a discussion and tabular presentation of the Company’s current contractual obligations by period, refer to Off-Balance Sheet Arrangements and Aggregate Contractual Obligations within the Capital Resources and Liquidity section of the MD&A.
The principal sources of operating funds are premiums, fees earned from assets under management and investment income, while investing cash flows originate from maturities and sales of invested assets.
The primary uses of funds are to pay claims, claim adjustment expenses, commissions and other underwriting expenses, to purchase new investments and to make dividend payments to the HFSG Holding Company.
The Company’s insurance operations consist of property and casualty insurance products (collectively referred to as “Property & Casualty Operations”) and life insurance and legacy annuity products (collectively referred to as “Life Operations”).
Property & Casualty Operations Property & Casualty Operations holds fixed maturity securities including a significant short-term investment position (securities with maturities of one year or less at the time of purchase) to meet liquidity needs.
As of December 31, 2013, Property & Casualty Operations’ fixed maturities, short-term investments, and cash are summarized as follows:
## Table 1 ##
Insurance operating costs and other expenses decreased $118 primarily due to a reduction in direct marketing expenses in Personal Lines.
Loss on extinguishment of debt decreased due to the redemption of $296 aggregate principal amount outstanding of 4.0% senior notes in 2015.
There were no early debt extinguishments in 2016.
Loss on reinsurance transaction in 2016 represents paid premium for an asbestos and environmental adverse development cover (“ADC”) reinsurance agreement with NICO, a subsidiary of Berkshire Hathaway Inc.  (“Berkshire”), to reduce uncertainty about potential adverse development.
For more information on this transaction, see MD&A -Critical Accounting Estimates, Annual Reserve Reviews.
Income tax benefit of $166 in 2016 compared to income tax expense of $289 in 2015, primarily due to a decrease in taxable income and the effect of $113 of federal tax credits and other tax benefits in 2016 associated with investments in solar energy partnerships, as well as tax benefits in 2016 from the sale of the Company's U. K property and casualty run-off subsidiaries.
Differences between the Company's effective income tax rate and the U. S.  statutory rate of 35% are due primarily to tax exempt interest earned on invested assets, changes in the valuation allowance recorded on capital loss carryovers and federal tax credits associated with investments in solar energy partnerships.
Income from discontinued operations, net of tax, decreased from 2015 to 2016 primarily due to lower tax benefits recognized in 2016, a write-off of DAC associated with fixed annuities, lower investment income and a reinsurance gain on disposition in 2015, partially offset by lower net realized capital losses.
In addition, the continued run-off of the variable and fixed annuity block resulted in lower fee income, partially offset by lower amortization of DAC and lower insurance operating costs and other expenses.
INVESTMENT RESULTS Composition of Invested Assets
## Table 2 ##
[1] Primarily relates to derivative instruments.
Year ended December 31, 2017 compared to the year ended December 31, 2016 Total investments increased primarily due to an increase in fixed maturities, AFS, short-term investments and mortgage loans.
Fixed maturities, AFS increased primarily due the transfer in of fixed maturities, AFS related to the acquisition of Aetna's U. S.  group life and disability business as well as an increase in valuations due to tighter credit spreads.
Short-term investments increased largely as a result of the Company's securities lending agreements.
For more information on the Company's securities lending agreements, see Note 6 - Investments.
Mortgage Loans increased largely due to originations of multifamily commercial whole loans.
THE HARTFORD FINANCIAL SERVICES GROUP, INC.  NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (continued) 11.
Reserve for Unpaid Losses and Loss Adjustment Expenses (continued) F-66 Group Life, Disability and Accident Products Reserves, Net of Reinsurance, that are Discounted
## Table 3 ##
Reserves are discounted at rates in effect at the time claims were incurred, ranging from 2.1% for life and disability reserves acquired from Aetna based on interest rates in effect at the acquisition date of November 1, 2017, to 8.0% for the Company’s pre-acquisition reserves for incurral year 1990, and vary by product.
Prior year's discount accretion has been calculated as the average reserve balance for the year times the weighted average discount rate.
The decrease in the weighted average discount rate for 2017 was primarily due to the fact that reserves for the Aetna U. S.  group life and disability business are discounted at market rates in effect as of the acquisition date.
Re-estimates of prior incurral years reserves in 2017 was driven by the following: ?
Group Disability- Prior period estimates decreased by approximately $125 driven by group long-term disability favorable claim incidence for incurral year 2016 and claim recoveries higher than prior reserve assumptions.  ?
Group Life and Accident (including Group Life Premium Waiver)- Contributing to an approximately $60 decrease in prior period reserve estimates was favorable claim incidence on group life premium waiver for incurral year 2016.
Re-estimates of prior incurral years reserves in 2016 was driven by the following: ?
Group Disability- Prior period estimates decreased by approximately $90 largely driven by group long-term disability claim recoveries higher than prior reserve assumptions, particularly in the older incurral years.
This favorability was partially offset by lower Social Security Disability approvals driven by lower approval rates and backlogs in the Social Security Administration.  ?
Group Life and Accident (including Group Life Premium Waiver)- Contributing to an approximately $75 decrease in prior period reserve estimates was favorable claim incidence on group life premium waiver for incurral year 2015.
Re-estimates of prior incurral years reserves in 2015 was driven by the following: ?
Group Disability- Prior period estimates decreased by approximately $90 largely driven by updated assumptions related to the probability and timing of long-term disability claim recoveries, which were updated to reflect recent favorable trends.
This favorability was partially offset by lower approval rates and backlogs in the Social Security Administration.  ?
Group Life and Accident (including Group Life Premium Waiver- Prior period estimates decreased by approximately $50 largely driven by favorable claim incidence and recovery experience on group life premium waiver.

Tables referenced above, in order (Table 0 first):
<table><tr><td></td><td>2004</td><td>2003</td><td>2002</td></tr><tr><td>Investment yield, after-tax</td><td>4.1%</td><td>4.2%</td><td>4.5%</td></tr><tr><td>Net realized capital gains (losses), after-tax</td><td>$87</td><td>$165</td><td>$-44</td></tr></table>
<table><tr><td>Fixed maturities</td><td>$24,704</td></tr><tr><td>Short-term investments</td><td>984</td></tr><tr><td>Cash</td><td>189</td></tr><tr><td>Less: Derivative collateral</td><td>241</td></tr><tr><td>Total</td><td>$25,636</td></tr></table>
<table><tr><td></td><td colspan="2">December 31, 2017</td><td colspan="2">December 31, 2016</td></tr><tr><td></td><td>Amount</td><td>Percent</td><td>Amount</td><td>Percent</td></tr><tr><td>Fixed maturities, available-for-sale ("AFS"), at fair value</td><td>$36,964</td><td>81.9%</td><td>$32,182</td><td>80.9%</td></tr><tr><td>Fixed maturities, at fair value using the fair value option ("FVO")</td><td>41</td><td>0.1%</td><td>211</td><td>0.5%</td></tr><tr><td>Equity securities, AFS, at fair value</td><td>1,012</td><td>2.3%</td><td>945</td><td>2.4%</td></tr><tr><td>Mortgage loans</td><td>3,175</td><td>7.0%</td><td>2,886</td><td>7.3%</td></tr><tr><td>Limited partnerships and other alternative investments</td><td>1,588</td><td>3.5%</td><td>1,527</td><td>3.8%</td></tr><tr><td>Other investments [1]</td><td>96</td><td>0.2%</td><td>111</td><td>0.3%</td></tr><tr><td>Short-term investments</td><td>2,270</td><td>5.0%</td><td>1,895</td><td>4.8%</td></tr><tr><td>Total investments</td><td>$45,146</td><td>100%</td><td>$39,757</td><td>100%</td></tr></table>
<table><tr><td></td><td colspan="9">For the years ended December 31,</td></tr><tr><td></td><td colspan="3">2017</td><td colspan="3">2016</td><td colspan="3">2015</td></tr><tr><td>Liability for unpaid losses and loss adjustment expenses, at undiscounted amounts</td><td>$9,071</td><td colspan="2"></td><td>$6,382</td><td colspan="2"></td><td>$6,565</td><td colspan="2"></td></tr><tr><td>Less: amount of discount</td><td colspan="3">1,536</td><td colspan="3">1,303</td><td colspan="3">1,382</td></tr><tr><td>Carrying value of liability for unpaid losses and loss adjustment expenses</td><td>$7,535</td><td colspan="2"></td><td>$5,079</td><td colspan="2"></td><td>$5,183</td><td colspan="2"></td></tr><tr><td>Weighted average discount rate</td><td colspan="3">3.5%</td><td colspan="3">4.3%</td><td colspan="3">4.4%</td></tr><tr><td>Range of discount rate</td><td>2.1%</td><td>-</td><td>8.0%</td><td>3.0%</td><td>-</td><td>8.0%</td><td>3.0%</td><td>-</td><td>8.0%</td></tr></table>

Question: What's the average of the Less: amount of discount in the years where Equity securities, AFS, at fair value for Amount is positive?
Answer: 1407
Reasoning program: add(1536,1303), add(#0,1382), divide(#1,3)