112 / sl green realty corp . 2017 annual report 20 . commitments and contingencies legal proceedings as of december a031 , 2017 , the company and the operating partnership were not involved in any material litigation nor , to management 2019s knowledge , was any material litigation threat- ened against us or our portfolio which if adversely determined could have a material adverse impact on us . environmental matters our management believes that the properties are in compliance in all material respects with applicable federal , state and local ordinances and regulations regarding environmental issues . management is not aware of any environmental liability that it believes would have a materially adverse impact on our financial position , results of operations or cash flows . management is unaware of any instances in which it would incur significant envi- ronmental cost if any of our properties were sold . employment agreements we have entered into employment agreements with certain exec- utives , which expire between december a02018 and february a02020 . the minimum cash-based compensation , including base sal- ary and guaranteed bonus payments , associated with these employment agreements total $ 5.4 a0million for 2018 . in addition these employment agreements provide for deferred compen- sation awards based on our stock price and which were valued at $ 1.6 a0million on the grant date . the value of these awards may change based on fluctuations in our stock price . insurance we maintain 201call-risk 201d property and rental value coverage ( includ- ing coverage regarding the perils of flood , earthquake and terrorism , excluding nuclear , biological , chemical , and radiological terrorism ( 201cnbcr 201d ) ) , within three property insurance programs and liability insurance . separate property and liability coverage may be purchased on a stand-alone basis for certain assets , such as the development of one vanderbilt . additionally , our captive insurance company , belmont insurance company , or belmont , pro- vides coverage for nbcr terrorist acts above a specified trigger , although if belmont is required to pay a claim under our insur- ance policies , we would ultimately record the loss to the extent of belmont 2019s required payment . however , there is no assurance that in the future we will be able to procure coverage at a reasonable cost . further , if we experience losses that are uninsured or that exceed policy limits , we could lose the capital invested in the damaged properties as well as the anticipated future cash flows from those plan trustees adopted a rehabilitation plan consistent with this requirement . no surcharges have been paid to the pension plan as of december a031 , 2017 . for the pension plan years ended june a030 , 2017 , 2016 , and 2015 , the plan received contributions from employers totaling $ 257.8 a0million , $ 249.5 a0million , and $ 221.9 a0million . our contributions to the pension plan represent less than 5.0% ( 5.0 % ) of total contributions to the plan . the health plan was established under the terms of collective bargaining agreements between the union , the realty advisory board on labor relations , inc . and certain other employees . the health plan provides health and other benefits to eligible participants employed in the building service industry who are covered under collective bargaining agreements , or other writ- ten agreements , with the union . the health plan is administered by a board of trustees with equal representation by the employ- ers and the union and operates under employer identification number a013-2928869 . the health plan receives contributions in accordance with collective bargaining agreements or participa- tion agreements . generally , these agreements provide that the employers contribute to the health plan at a fixed rate on behalf of each covered employee . for the health plan years ended , june a030 , 2017 , 2016 , and 2015 , the plan received contributions from employers totaling $ 1.3 a0billion , $ 1.2 a0billion and $ 1.1 a0billion , respectively . our contributions to the health plan represent less than 5.0% ( 5.0 % ) of total contributions to the plan . contributions we made to the multi-employer plans for the years ended december a031 , 2017 , 2016 and 2015 are included in the table below ( in thousands ) : .
what was the percentage increase in the pension plan contributions from 2015 to 2016
401 ( k ) plan in august a01997 , we implemented a 401 ( k ) a0savings/retirement plan , or the 401 ( k ) a0plan , to cover eligible employees of ours , and any designated affiliate . the 401 ( k ) a0plan permits eligible employees to defer up to 15% ( 15 % ) of their annual compensation , subject to certain limitations imposed by the code . the employees 2019 elective deferrals are immediately vested and non-forfeitable upon contribution to the 401 ( k ) a0plan . during a02003 , we amended our 401 ( k ) a0plan to pro- vide for discretionary matching contributions only . for 2017 , 2016 and 2015 , a matching contribution equal to 50% ( 50 % ) of the first 6% ( 6 % ) of annual compensation was made . for the year ended december a031 , 2017 , we made a matching contribution of $ 728782 . for the years ended december a031 , 2016 and 2015 , we made matching contribu- tions of $ 566000 and $ 550000 , respectively. .