programs may offer premium rates that are below prevalent single premium LPMI rates. While we view these programs as competing with traditional private mortgage insurance, we have participated in them and may participate in future GSE or other programs.
We are continuing to monitor our exposure to such loans and may take further action.
Persistency. Our persistency at December 31, 2019 was 75.8% compared to 81.7% at December 31, 2018. Since 2000, our year-end persistency ranged from a high of 84.7% at December 31, 2009 to a low of 47.1% at December 31, 2003.
More of an adverse impact as the 2019 periods included ceded premiums under our excess of loss reinsurance transactions (Home Re Transactions), which were not in effect for all of 2018.
The amount of our NIW subject to our QSR Transactions as shown in the following table will vary from period to period in part due to coverage limits that may be triggered depending on the mix of our risk written during the period.
2019 compared to 2018. Net investment income increased 18% to $167 million in 2019 compared to $141 million in 2018. The increase in investment income was due to a higher average investment portfolio balance.
2019 compared to 2018. Other revenue increased to $11 million in 2019 from $9 million in 2018, primarily due to higher contract underwriting revenues.
New notices declined in 2019 compared to 2018 and 2018 compared to 2017 due to favorable economic conditions and an improving risk profile of our RIF. However, 2017 new notice activity also included the impact of hurricane activity.
The underwriting expense ratio increased in 2019 compared with 2018 due to an increase in underwriting expenses partially offset by slightly higher NPW. The increase in the underwriting expense ratio in 2018 when compared to 2017 was due to an increase in expenses and a decrease in our NPW.
The following sections focus on the assets and liabilities experiencing major developments in 2019.
Maximize total return with emphasis on yield, subject to our other objectives
insurance subsidiaries are the principal sources of holding company cash inflow. MGIC is the principal source of dividends, and their payment is restricted by insurance regulation. See Note 14 - “Statutory Information” to our consolidated financial statement for additional information about MGIC’s dividend restrictions. The payment of dividends from MGIC is also influenced by our view of the appropriate level of PMIERs Available Assets to maintain an excess over Minimum Required Assets. Other sources of holding company liquidity include raising capital in the public markets. The ability to raise capital in the public markets is subject to prevailing market conditions, investor demand for the securities to be issued, and our deemed creditworthiness.
Scheduled debt maturities beyond the next twelve months include $425 million of our 5.75% Notes in 2023 and $389.5 million of our 9% Debentures in 2063, of which MGIC owns $132.7 million. The principal amount of the 9% Debentures is currently convertible, at the holder’s option, at an initial conversion rate, which is subject to adjustment, of 74.4718 common shares per $1,000 principal amount of debentures. This represents an initial conversion price of approximately $13.43 per share. We may redeem the 9% Debentures in whole or in part from time to time, at our option, at a redemption price equal to 100% of the principal amount of the 9% Debentures being redeemed, plus any accrued and unpaid interest, if the closing sale price of our common stock exceeds $17.46 for at least 20 of the 30 trading days preceding notice of the redemption.
Our long-term debt obligations as of December 31, 2019 include their related interest and are discussed in Note 7 - “Debt” to our consolidated financial statements and under “Liquidity and Capital Resources” above. Our operating lease obligations include operating leases on certain office space, data processing equipment and autos, as discussed in Note 16 - “Leases” to our consolidated financial statements. Purchase obligations consist primarily of agreements to purchase items related to our ongoing infrastructure projects and information technology investments in the normal course of business.
The accounting policies described below require significant judgments and estimates in the preparation of our consolidated financial statements.
Equity securities: Consist of actively traded, exchange-listed equity securities with valuations derived from quoted prices for identical assets in active markets that we can access.
Fair value roll-forward for financial instruments classified as Level 3 for the year ended December 31, 2019
in the delinquent inventory, such as percentages of delinquencies that have resulted in a claim, the amount of the claims relative to the average loan exposure, changes in the relative level of delinquencies by geography and changes in average loan exposure.
A roll-forward of our primary delinquent inventory for the years ended December 31, 2019, 2018, and 2017 appears in table 8.3 below. The information concerning new notices and cures is compiled from monthly reports received from loan servicers. The level of new notice and cure activity reported in a particular month can be influenced by, among other things, the date on which a servicer generates its report, the number of business days in a month and transfers of servicing between loan servicers.
Pool insurance default inventory decreased to 653 at December 31, 2019 from 859 at December 31, 2018 and 1,309 at December 31, 2017.
2015 QSR Transaction. We terminated a portion of our 2015 QSR Transaction effective June 30, 2019 and entered into an amended quota share reinsurance agreement with certain participants from the existing reinsurance panel that effectively reduces the quota share cede rate from 30% to 15% on the remaining eligible insurance. During the second quarter of 2019, we incurred a termination fee of $6.8 million, which was paid to participants of the reinsurance panel that are not participating in the amended 2015 QSR Transaction. Under the amended 2015 QSR Transaction we cede losses and premiums on eligible insurance written before 2017 through December 31, 2031, at which time the agreement expires. Early termination of the amended agreement can be elected by us on or after June 30, 2021, bi-annually thereafter for no fee, or under specified scenarios, including if we will receive less than 90% of the full credit amount under the PMIERs, full financial statement credit or full credit under applicable regulatory capital requirements for the risk ceded in any required calculation period. Generally, under our amended 2015 QSR Transaction, we will receive an annual profit commission provided the annual loss ratio on the loans covered under the transactions remains below 68%.
The structure of the 2020 QSR Transaction is a 30% quota share on 2020 NIW, with an option to reduce the cede rate to either 25.0% or 20% effective July 1, 2021 or semiannually thereafter. Generally, under the 2020 QSR Transaction, we will receive an annual profit commission provided the annual loss ratio on the loans covered under the transactions remains below 62%.
Under the 2021 QSR Transaction, we cede losses incurred and premiums on or after the effective date through December 31, 2032 for 2021 NIW, at which time the agreement expires. Early termination of the agreement can be elected by us effective December 31, 2023, and bi-annually thereafter, for a fee, or under specified scenarios for no fee upon prior written notice, including if we will receive less than 90% of the full credit amount under the PMIERs for the risk ceded in any required calculation period.
Table 11.7 shows the amount of amortization on components of net periodic benefit costs expected to be recognized during the year ending December 31, 2020.
Tables 11.11a and 11.11b set forth the other postretirement benefits plan assets at fair value as of December 31, 2019 and 2018. All are Level 1 assets.
Tables 11.12 and 11.13 show the current and estimated future contributions and benefit payments.
Repurchases may be made from time to time on the open market (including through 10b5-1 plans) or through privately negotiated transactions. The repurchase program may be suspended for periods or discontinued at any time.
3.4 million shares were available for future grant under the 2015 plan.
Addressing the matter involved performing procedures and evaluating audit evidence in connection with forming our overall opinion on the consolidated financial statements. These procedures included testing the effectiveness of controls relating to the valuation of loss reserves, including controls over the development of significant assumptions, including the claim rate and claim severity. These procedures also included, among others, the involvement of professionals with specialized skill and knowledge to assist in developing an independent estimate of loss reserves using historical experience and comparing this independent estimate to management’s recorded loss reserves to evaluate the reasonableness of the recorded loss reserves. Developing the independent estimate involved testing the completeness, accuracy, and relevance of data provided by management and independently developing assumptions, including the claim rate and claim severity.