Earnings from operations in 2017 increased by $4,444 million compared with 2016, primarily due to higher earnings at BCA and BDS, and higher unallocated pension income, which more than offset other unallocated items and eliminations.
BCA's 2017 earnings increased by $3,437 million primarily reflecting lower reach-forward losses, lower research and development costs, and improved margins reflecting favorable cost performance, which more than offset the impact of lower revenues.
In 2016, BCA recorded reach-forward losses of $1,258 million on the 747 program and reclassified $1,235 million of 787 flight test aircraft inventory costs to research and development expense.
BDS earnings from operations in 2017 increased by $257 million compared with 2016 primarily due to lower charges on the KC-46A Tanker and Commercial Crew programs, which more than offset the impact of fewer C-17 deliveries and Apache delivery mix.
Earnings from operations in 2016 decreased by $1,609 million compared with 2015 due to lower earnings at BCA, partially offset by the change in unallocated pension and postretirement income/(expense).
BCA earnings in 2016 decreased by $2,289 million primarily due to the reclassification of $1,235 million of 787 flight test aircraft costs to research and development and higher reach-forward losses on the 747 and KC-46ATanker programs.
The reclassification of flight test aircraft costs was recorded in the second quarter of 2016 as a result of our determination that two 787 flight test aircraft were no longer commercially saleable.
The change in the unallocated pension and postretirement income/(expense) in 2016 was primarily driven by lower service costs and lower amortization of actuarial losses.
During 2017, 2016 and 2015, we recorded reach-forward losses on the KC-46A Tanker program.
In 2017, we recorded charges of $471 million, of which $378 million was recorded at BCA and $93 million at BDS.
During 2016, we recorded charges of $1,128 million: $772 million at BCA and $356 million at BDS.
During 2015, we recorded charges of $835 million: $513 million at BCA and $322 million at BDS.
During 2016 and 2015 we recorded reach-forward losses on the 747 program of $1,258 million and $885 million.
Core operating earnings for 2017 increased by $3,506 million compared with 2016 primarily due to lower reach forward losses and the reclassification of costs related to the 787 flight test aircraft in 2016.
Core operating earnings in 2016 decreased by $2,227 million compared with 2015 primarily due to the reclassification of costs related to the 787 flight test aircraft and higher charges on the 747 and KC-46A Tanker programs described above.
Unallocated Items, Eliminations and Other The most significant items included in Unallocated items, eliminations and other are shown in the following table:
## Table 0 ##
* Core operating earnings is a Non-GAAP measure that excludes certain components of pension and other postretirement benefit expense.
See pages 39 - 40.
Notes to the Financial Statements — Continued Note O – Derivative Instruments and Hedging Activities Con Edison’s subsidiaries hedge market price fluctuations associated with physical purchases and sales of electricity, natural gas and steam by using derivative instruments including futures, forwards, basis swaps, options, transmission congestion contracts and financial transmission rights contracts.
Derivatives are recognized on the balance sheet at fair value (See Note P), unless an exception is available under the accounting rules for derivatives and hedging.
Qualifying derivative contracts that have been designated as normal purchases or normal sales contracts are not reported at fair value under the accounting rules.
The fair values of the Companies’ commodity derivatives including the offsetting of assets and liabilities on the consolidated balance sheet at December 31, 2014 and 2013 were:
## Table 1 ##
(a) Derivative instruments and collateral were set off on the consolidated balance sheet as applicable under the accounting rules.
The Companies enter into master agreements for their commodity derivatives.
These agreements typically provide setoff in the event of contract termination.
In such case, generally the non-defaulting party’s payable will be set-off by the defaulting party’s payable.
The non-defaulting party will customarily notify the defaulting party within a specific time period and come to an agreement on the early termination amount.
(b) At December 31, 2014 and 2013, margin deposits for Con Edison ($27 million and $17 million, respectively) and CECONY ($25 million and $16 million, respectively) were classified as derivative assets in the balance sheet, but not included in the table.
Margin is collateral, typically cash, that the holder of a derivative instrument is required to deposit in order to transact on an exchange and to cover its potential losses with its broker or the exchange.
The Utilities generally recover their prudently incurred fuel, purchased power and gas costs, including hedging gains and losses, in accordance with rate provisions approved by the applicable state utility regulators.
See “Recoverable Energy Costs” in Note A.
In accordance with the accounting rules for regulated operations, the Utilities record a regulatory asset or liability to defer recognition of unrealized gains and losses on their electric and gas derivatives.
As gains and losses are realized in future periods, they will be recognized as purchased power, gas and fuel costs in the Companies’ consolidated income statements.
Con Edison’s competitive energy businesses record realized and unrealized gains and losses on their derivative contracts in purchased power, gas purchased for resale and non-utility revenue in the reporting period in which they occur.
Management believes that these derivative instruments represent economic hedges that mitigate exposure to fluctuations in commodity prices.
acquire operations and facilities from municipalities and other local governments, as they increasingly seek to raise capital and reduce risk.
We realize synergies from consolidating businesses into our existing operations, whether through acquisitions or public-private partnerships, which allows us to reduce capital expenditures and expenses associated with truck routing, personnel, fleet maintenance, inventories and back-office administration.
Operating Model The goal of our operating model pillar is to deliver a consistent, high-quality service to all of our customers through the Republic Way: One Way.
Everywhere.
Every day.
This approach of developing standardized processes with rigorous controls and tracking allows us to leverage our scale and deliver durable operational excellence.
The Republic Way is the key to harnessing the best of what we do as operators and translating that across all facets of our business.
A key enabler of the Republic Way is our organizational structure that fosters a high performance culture by maintaining 360-degree accountability and full profit and loss responsibility with local management, supported by a functional structure to provide subject matter expertise.
This structure allows us to take advantage of our scale by coordinating functionally across all of our markets, while empowering local management to respond to unique market dynamics.
We have rolled out several productivity and cost control initiatives designed to deliver the best service possible to our customers in the most efficient and environmentally sound way.
Fleet Automation Approximately 75% of our residential routes have been converted to automated single-driver trucks.
By converting our residential routes to automated service, we reduce labor costs, improve driver productivity, decrease emissions and create a safer work environment for our employees.
Additionally, communities using automated vehicles have higher participation rates in recycling programs, thereby complementing our initiative to expand our recycling capabilities.
Fleet Conversion to Compressed Natural Gas (CNG) Approximately 19% of our fleet operates on natural gas.
We expect to continue our gradual fleet conversion to CNG as part of our ordinary annual fleet replacement process.
We believe a gradual fleet conversion is the most prudent approach to realizing the full value of our previous fleet investments.
Approximately 30% of our replacement vehicle purchases during 2017 were CNG vehicles.
We believe using CNG vehicles provides us a competitive advantage in communities with strict clean emission initiatives that focus on protecting the environment.
Although upfront capital costs are higher, using CNG reduces our overall fleet operating costs through lower fuel expenses.
As of December 31, 2017, we operated 37 CNG fueling stations.
Standardized Maintenance Based on an industry trade publication, we operate the seventh largest vocational fleet in the United States.
As of December 31, 2017, our average fleet age in years, by line of business, was as follows:
## Table 2 ##
Landfill depletion and amortization expense increased primarily due to increased landfill disposal volumes and an overall increase in our average depletion and amortization rate.
The increase in expense was partially offset by favorable amortization adjustments recorded during 2016 of $6.5 million relative to asset retirement obligations, compared to favorable amortization adjustments of $0.7 million during 2015.
Amortization of Other Intangible Assets and Other Assets Expenses for amortization of other intangible assets and other assets were $71.0 million, $71.3 million and $71.9 million for the years ended December 31, 2017, 2016 and 2015, respectively, or 0.7% of revenue for 2017 and 0.8% for 2016 and 2015.
Our other intangible assets and other assets primarily relate to customer relationships, franchise agreements, other municipal agreements, and, to a lesser extent, non-compete agreements and trade names.
The changes in amortization expense are the result of assets acquired in the acquisitions of various waste businesses throughout the year, offset by certain intangible assets now being fully amortized.
Accretion Expense Accretion expense was $79.8 million, $79.1 million and $79.4 million, or 0.8% of revenue, for the years ended December 31, 2017 and 2016, and 0.9% of revenue for the year ended December 31, 2015.
Accretion expense has remained relatively unchanged as our asset retirement obligations remained relatively consistent period over period.
Selling, General and Administrative Expenses Selling, general and administrative expenses include salaries, health and welfare benefits, and incentive compensation for corporate and field general management, field support functions, sales force, accounting and finance, legal, management information systems, and clerical and administrative departments.
Other expenses include rent and office costs, fees for professional services provided by third parties, legal settlements, marketing, investor and community relations services, directors’ and officers’ insurance, general employee relocation, travel, entertainment and bank charges.
Restructuring charges are excluded from selling, general and administrative expenses and are discussed separately below.
The following table summarizes our selling, general and administrative expenses for the years ended December 31, 2017, 2016 and 2015 (in millions of dollars and as a percentage of revenue):
## Table 3 ##
These cost categories may change from time to time and may not be comparable to similarly titled categories used by other companies.
As such, you should take care when comparing our selling, general and administrative expenses by cost component to those of other companies.
Selling, General and Administrative Expenses – 2017 compared to 2016 Salaries increased primarily due to higher incentive pay and wages and other payroll related items resulting from merit increases.
Other selling, general and administrative expenses increased primarily due a favorable legal settlement during 2016.
Additionally, we had an increase in acquisition-related transaction costs associated with our increased acquisition activity during the year.

<table><tr><td>Years ended December 31,</td><td>2017</td><td>2016</td><td>2015</td></tr><tr><td>Share-based plans</td><td>-$77</td><td>-$66</td><td>-$76</td></tr><tr><td>Deferred compensation</td><td>-240</td><td>-46</td><td>-63</td></tr><tr><td>Eliminations and other</td><td>-738</td><td>-621</td><td>-601</td></tr><tr><td>Sub-total (included in core operating earnings*)</td><td>-1,055</td><td>-733</td><td>-740</td></tr><tr><td>Pension</td><td>1,120</td><td>217</td><td>-421</td></tr><tr><td>Postretirement</td><td>188</td><td>153</td><td>123</td></tr><tr><td>Pension and other postretirement benefit income/(expense)(excluded from core operating earnings*)</td><td>1,308</td><td>370</td><td>-298</td></tr><tr><td>Total unallocated items, eliminations and other</td><td>$253</td><td>-$363</td><td>-$1,038</td></tr></table>
<table><tr><td> (Millions of Dollars)</td><td colspan="3">2014</td><td colspan="3">2013</td></tr><tr><td> Balance Sheet Location</td><td>Gross Amountsof Recognized Assets/ (Liabilities)</td><td>Gross Amounts Offset</td><td>Net Amounts of Assets/ (Liabilities)(a)</td><td>Gross Amountsof Recognized Assets/ (Liabilities)</td><td>Gross Amounts Offset</td><td>Net Amounts of Assets/ (Liabilities)(a)</td></tr><tr><td> Con Edison</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Fair value of derivative assets</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Current</td><td>$111</td><td>$-67</td><td>$44(b)</td><td>$134</td><td>$-77</td><td>$57(b)</td></tr><tr><td>Non-current</td><td>34</td><td>-23</td><td>11</td><td>32</td><td>-24</td><td>8</td></tr><tr><td>Total fair value of derivative assets</td><td>$145</td><td>$-90</td><td>$55</td><td>$166</td><td>$-101</td><td>$65</td></tr><tr><td>Fair value of derivative liabilities</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Current</td><td>$-242</td><td>$139</td><td>$-103</td><td>$-82</td><td>$72</td><td>$-10</td></tr><tr><td>Non-current</td><td>-66</td><td>91</td><td>25</td><td>-31</td><td>26</td><td>-5</td></tr><tr><td>Total fair value of derivative liabilities</td><td>$-308</td><td>$230</td><td>$-78</td><td>$-113</td><td>$98</td><td>$-15</td></tr><tr><td>Net fair value derivative assets/(liabilities)</td><td>$-163</td><td>$140</td><td>$-23(b)</td><td>$53</td><td>$-3</td><td>$50(b)</td></tr><tr><td> CECONY</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Fair value of derivative assets</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Current</td><td>$26</td><td>$-15</td><td>$11(b)</td><td>$27</td><td>$-19</td><td>$8(b)</td></tr><tr><td>Non-current</td><td>22</td><td>-20</td><td>2</td><td>14</td><td>-13</td><td>1</td></tr><tr><td>Total fair value of derivative assets</td><td>$48</td><td>$-35</td><td>$13</td><td>$41</td><td>$-32</td><td>$9</td></tr><tr><td>Fair value of derivative liabilities</td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Current</td><td>$-96</td><td>$48</td><td>$-48</td><td>$-32</td><td>$21</td><td>$-11</td></tr><tr><td>Non-current liabilities</td><td>-42</td><td>32</td><td>-10</td><td>-19</td><td>16</td><td>-3</td></tr><tr><td>Total fair value of derivative liabilities</td><td>$-138</td><td>$80</td><td>$-58</td><td>$-51</td><td>$37</td><td>$-14</td></tr><tr><td>Net fair value derivative assets/(liabilities)</td><td>$-90</td><td>$45</td><td>$-45(b)</td><td>$-10</td><td>$5</td><td>$-5(b)</td></tr></table>
<table><tr><td></td><td>Approximate Number of Vehicles</td><td>Approximate Average Age</td></tr><tr><td>Residential</td><td>7,200</td><td>7.5</td></tr><tr><td>Small-container</td><td>4,600</td><td>7.1</td></tr><tr><td>Large-container</td><td>4,100</td><td>8.8</td></tr><tr><td>Total</td><td>15,900</td><td>7.7</td></tr></table>
<table><tr><td></td><td colspan="2">2017</td><td colspan="2">2016</td><td colspan="2">2015</td></tr><tr><td>Salaries</td><td>$706.3</td><td>7.0%</td><td>$646.3</td><td>6.9%</td><td>$636.6</td><td>7.0%</td></tr><tr><td>Provision for doubtful accounts</td><td>30.6</td><td>0.3</td><td>20.4</td><td>0.2</td><td>22.7</td><td>0.2</td></tr><tr><td>Other</td><td>320.5</td><td>3.2</td><td>303.1</td><td>3.2</td><td>323.8</td><td>3.6</td></tr><tr><td>Total selling, general and administrative expenses</td><td>$1,057.4</td><td>10.5%</td><td>$969.8</td><td>10.3%</td><td>$983.1</td><td>10.8%</td></tr></table>

Question: what is the approximately number of vehicles that were converted to compressed natural gas
Answer: 3021