table of contents seasonality our business experiences seasonality that varies by product line .because more construction and do-it-yourself projects occur during the second and third calendar quarters of each year in the northern hemisphere , our security product sales , typically , are higher in those quarters than in the first and fourth calendar quarters .however , our interflex business typically experiences higher sales in the fourth calendar quarter due to project timing .revenue by quarter for the years ended december 31 , 2015 , 2014 and 2013 are as follows: .
[['', 'first quarter', 'second quarter', 'third quarter', 'fourth quarter'], ['2015', '22% ( 22 % )', '25% ( 25 % )', '26% ( 26 % )', '27% ( 27 % )'], ['2014', '22% ( 22 % )', '25% ( 25 % )', '26% ( 26 % )', '27% ( 27 % )'], ['2013', '23% ( 23 % )', '26% ( 26 % )', '26% ( 26 % )', '25% ( 25 % )']]
2015 fourth quarter revenue includes the full-quarter impact of the acquisitions of simonsvoss , axa and milre .employees as of december 31 , 2015 , we had more than 9400 employees , approximately 26% ( 26 % ) of whom have the terms of their employment covered under collective bargaining agreements .this includes non-management european employees who are represented by national and local works councils .environmental regulation we have a dedicated environmental program that is designed to reduce the utilization and generation of hazardous materials during the manufacturing process as well as to remediate identified environmental concerns .as to the latter , we are currently engaged in site investigations and remediation activities to address environmental cleanup from past operations at current and former manufacturing facilities .we are sometimes a party to environmental lawsuits and claims and have received notices of potential violations of environmental laws and regulations from the u.s .environmental protection agency ( the "epa" ) and similar state authorities .we have also been identified as a potentially responsible party ( "prp" ) for cleanup costs associated with off-site waste disposal at federal superfund and state remediation sites .for all such sites , there are other prps and , in most instances , our involvement is minimal .in estimating our liability , we have assumed that we will not bear the entire cost of remediation of any site to the exclusion of other prps who may be jointly and severally liable .the ability of other prps to participate has been taken into account , based on our understanding of the parties 2019 financial condition and probable contributions on a per site basis .additional lawsuits and claims involving environmental matters are likely to arise from time to time in the future .we incurred $ 4.4 million , $ 2.9 million , and $ 2.1 million of expenses during the years ended december 31 , 2015 , 2014 , and 2013 , respectively , for environmental remediation at sites presently or formerly owned or leased by us .as of december 31 , 2015 and 2014 , we have recorded reserves for environmental matters of $ 15.2 million and $ 8.8 million .of these amounts $ 2.8 million and $ 2.4 million , respectively , relate to remediation of sites previously disposed by us .given the evolving nature of environmental laws , regulations and technology , the ultimate cost of future compliance is uncertain .available information we are required to file annual , quarterly , and current reports , proxy statements , and other documents with the u.s .securities and exchange commission ( "sec" ) .the public may read and copy any materials filed with the sec at the sec 2019s public reference room at 100 f street , n.e. , washington , d.c .20549 .the public may obtain information on the operation of the public reference room by calling the sec at 1-800-sec-0330 .also , the sec maintains an internet website that contains reports , proxy and information statements , and other information regarding issuers that file electronically with the sec .the public can obtain any documents that are filed by us at http://www.sec.gov .in addition , this annual report on form 10-k , as well as future quarterly reports on form 10-q , current reports on form 8-k and any amendments to all of the foregoing reports , are made available free of charge on our internet website ( http://www.allegion.com ) as soon as reasonably practicable after such reports are electronically filed with or furnished to the sec .the contents of our website are not incorporated by reference in this report. .

Question: considering the year 2015 , what is the percentage of reserves for environmental matters related to remediation of sites?
Answer: 18.42%
Explanation: it is the value of the reserves for remediation of sites divided by the total value of all reserves for environmental matters.\\n