human
the company has also encountered various quality issues on its aircraft carrier construction and overhaul programs and its virginia-class submarine construction program at its newport news location. these primarily involve matters related to filler metal used in pipe welds identified in 2007, and issues associated with non-nuclear weld inspection and the installation of weapons handling equipment on certain submarines, and certain purchased material quality issues identified in 2009. the company does not believe that resolution of these issues will have a material effect upon its consolidated financial position, results of operations or cash flows. environmental matters 2014the estimated cost to complete environmental remediation has been accrued where it is probable that the company will incur such costs in the future to address environmental conditions at currently or formerly owned or leased operating facilities, or at sites where it has been named a potentially responsible party (201cprp 201d) by the environmental protection agency, or similarly designated by another environmental agency, and these costs can be estimated by management. these accruals do not include any litigation costs related to environmental matters, nor do they include amounts recorded as asset retirement obligations. to assess the potential impact on the company 2019s consolidated financial statements, management estimates the range of reasonably possible remediation costs that could be incurred by the company, taking into account currently available facts on each site as well as the current state of technology and prior experience in remediating contaminated sites. these estimates are reviewed periodically and adjusted to reflect changes in facts and technical and legal circumstances. management estimates that as of december 31, 2011, the probable future costs for environmental remediation is $3 million, which is accrued in other current liabilities. factors that could result in changes to the company 2019s estimates include: modification of planned remedial actions, increases or decreases in the estimated time required to remediate, changes to the determination of legally responsible parties, discovery of more extensive contamination than anticipated, changes in laws and regulations affecting remediation requirements, and improvements in remediation technology. should other prps not pay their allocable share of remediation costs, the company may have to incur costs exceeding those already estimated and accrued. in addition, there are certain potential remediation sites where the costs of remediation cannot be reasonably estimated. although management cannot predict whether new information gained as projects progress will materially affect the estimated liability accrued, management does not believe that future remediation expenditures will have a material effect on the company 2019s consolidated financial position, results of operations or cash flows. financial arrangements 2014in the ordinary course of business, hii uses standby letters of credit issued by commercial banks and surety bonds issued by insurance companies principally to support the company 2019s self-insured workers 2019 compensation plans. at december 31, 2011, there were $121 million of standby letters of credit issued but undrawn and $297 million of surety bonds outstanding related to hii. u.s. government claims 2014from time to time, the u.s. government advises the company of claims and penalties concerning certain potential disallowed costs. when such findings are presented, the company and u.s. government representatives engage in discussions to enable hii to evaluate the merits of these claims as well as to assess the amounts being claimed. the company does not believe that the outcome of any such matters will have a material effect on its consolidated financial position, results of operations or cash flows. collective bargaining agreements 2014the company believes that it maintains good relations with its approximately 38000 employees of which approximately 50% (50%) are covered by a total of 10 collective bargaining agreements. the company expects to renegotiate renewals of each of its collective bargaining agreements between 2013 and 2015 as they approach expiration. collective bargaining agreements generally expire after three to five years and are subject to renegotiation at that time. it is not expected that the results of these negotiations, either individually or in the aggregate, will have a material effect on the company 2019s consolidated results of operations. operating leases 2014rental expense for operating leases was $44 million in 2011, $44 million in 2010, and $48 million in 2009. these amounts are net of immaterial amounts of sublease rental income. minimum rental commitments under long- term non-cancellable operating leases for the next five years and thereafter are: ($in millions).
| 2012 | $21 |
| --------- | --------- |
| 2013 | 17 |
| 2014 | 15 |
| 2015 | 13 |
| 2016 | 10 |
| Thereafter | 48 |
| Total | $124 |
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Please answer the following questions with expressions if necessary.
what is the sum of the average operating leases 2014 rental expense for operating leases for 2011 and 2010?
assistant
add(44, 44)
human
what is the sum including 2009?
assistant
add(44, 44), add(#0, 48)
human
what is the average value per year?
assistant
add(44, 44), add(#0, 48), divide(#1, const_3)