Year % gross 1991 21.0225105285645 1992 19.6107692718506 1993 15.7152700424194 1994 14.8639497756958 1995 12.7728595733643 1996 9.94486045837402 1997 8.83257961273193 1998 7.46058988571167 1999 6.76291990280151 2000 6.6774001121521 2001 6.94275999069214 2002 7.79593992233276 2003 8.38387966156006 2004 8.8274097442627 2005 8.72694969177246 2006 8.69680976867676 2007 8.67465019226074 2008 8.41759967803955 2009 8.24730968475342 2010 7.85563993453979 2011 8.22412967681885 2012 8.91586017608643 2013 8.80245971679688 2014 9.31472969055176 2015 9.57907009124756 2016 9.60729026794434 2017 9.18045043945313