Year % gross 1971 3.92138004302979 1972 4.4039101600647 1973 5.22275018692017 1974 5.86882019042969 1975 6.69216012954712 1976 7.89107990264893 1977 8.68194007873535 1978 9.19472026824951 1979 9.62430953979492 1980 10.0588502883911 1981 10.934229850769 1982 11.6667995452881 1983 12.2068395614624 1984 12.460410118103 1985 12.1803703308105 1986 10.8762702941895 1987 10.4848299026489 1988 11.7480697631836 1989 10.2561597824097 1990 9.64068031311035 1991 8.59519958496094 2001 24.9822692871094 2002 26.443790435791 2003 24.6022205352783 2004 24.7853908538818 2005 26.3567695617676 2006 26.914680480957 2007 25.2448101043701 2008 28.0469799041748 2009 28.0995998382568 2010 29.2879295349121 2011 24.7804203033447 2012 25.1834392547607 2013 27.1532096862793 2014 27.8057994842529 2015 32.4894790649414 2016 32.5847702026367 2017 33.958381652832 2018 37.7170791625977 2020 39.7496109008789 2022 38.0330085754395