Year % of revenue 2003 5.838477028476372 2004 4.361873990306947 2005 4.436532252664361 2006 4.0275535618340745 2007 4.1711560505924075 2008 7.168660652404414 2009 12.787967547688902 2010 7.079121937024905 2011 6.93661624223202 2012 7.0157300258243795 2013 6.700311141118844 2014 7.841853902788457 2015 5.606791172823934 2016 7.510091774646685