table of contents to seek an international solution through icao and that will allow the u.s .
secretary of transportation to prohibit u.s .
airlines from participating in the ets .
ultimately , the scope and application of ets or other emissions trading schemes to our operations , now or in the near future , remains uncertain .
similarly , within the u.s. , there is an increasing trend toward regulating ghg emissions directly under the caa .
in response to a 2012 ruling by the u.s .
court of appeals district of columbia circuit requiring the epa to make a final determination on whether aircraft ghg emissions cause or contribute to air pollution , which may reasonably be anticipated to endanger public health or welfare , the epa announced in september 2014 that it is in the process of making a determination regarding aircraft ghg emissions and anticipates proposing an endangerment finding by may 2015 .
if the epa makes a positive endangerment finding , the epa is obligated under the caa to set ghg emission standards for aircraft .
several states are also considering or have adopted initiatives to regulate emissions of ghgs , primarily through the planned development of ghg emissions inventories and/or regional ghg cap and trade programs .
these regulatory efforts , both internationally and in the u.s .
at the federal and state levels , are still developing , and we cannot yet determine what the final regulatory programs or their impact will be in the u.s. , the eu or in other areas in which we do business .
depending on the scope of such regulation , certain of our facilities and operations may be subject to additional operating and other permit requirements , potentially resulting in increased operating costs .
the environmental laws to which we are subject include those related to responsibility for potential soil and groundwater contamination .
we are conducting investigation and remediation activities to address soil and groundwater conditions at several sites , including airports and maintenance bases .
we anticipate that the ongoing costs of such activities will not have a material impact on our operations .
in addition , we have been named as a potentially responsible party ( prp ) at certain superfund sites .
our alleged volumetric contributions at such sites are relatively small in comparison to total contributions of all prps ; we anticipate that any future payments of costs at such sites will not have a material impact on our operations .
future regulatory developments future regulatory developments and actions could affect operations and increase operating costs for the airline industry , including our airline subsidiaries .
see part i , item 1a .
risk factors 2013 201cif we are unable to obtain and maintain adequate facilities and infrastructure throughout our system and , at some airports , adequate slots , we may be unable to operate our existing flight schedule and to expand or change our route network in the future , which may have a material adverse impact on our operations , 201d 201cour business is subject to extensive government regulation , which may result in increases in our costs , disruptions to our operations , limits on our operating flexibility , reductions in the demand for air travel , and competitive disadvantages 201d and 201cwe are subject to many forms of environmental regulation and may incur substantial costs as a result 201d for additional information .
employees and labor relations the airline business is labor intensive .
in 2014 , salaries , wages and benefits were one of our largest expenses and represented approximately 25% ( 25 % ) of our operating expenses .
the table below presents our approximate number of active full-time equivalent employees as of december 31 , 2014 .
american us airways wholly-owned regional carriers total .

american
us airways
wholly-owned regional carriers
total
pilots
8600
4400
3200
16200
flight attendants
15900
7700
1800
25400
maintenance personnel
10800
3600
1700
16100
fleet service personnel
8600
6200
2500
17300
passenger service personnel
9100
6100
7300
22500
administrative and other
8600
4800
2400
15800
total
61600
32800
18900
113300

.

Question: what percentage of approximate number of active full-time equivalent employees are passenger service personnel ?
Answer: 19.9%
Calculation: divide(22500, 113300)