Year % gross 1970 7.90345001220703 1971 7.83795976638794 1972 7.7214298248291 1973 7.69097995758057 1974 7.60192012786865 1975 7.79732990264893 1976 8.25051021575928 1977 8.61993026733398 1978 8.42273998260498 1979 8.6315803527832 1980 8.81035041809082 1981 9.13556957244873 1982 9.45890045166016 1983 9.63582038879395 1984 9.94130992889404 1985 10.1729097366333 1986 10.3182401657104 1987 10.4616203308105 1988 10.2676601409912 1989 10.5998802185059 1990 10.6705799102783 1991 10.7841300964355 1992 10.7462902069092 1993 11.0166397094727 1994 11.2185001373291 1995 11.412449836731 1996 11.7473802566528 1997 11.9833698272705 1998 12.3512096405029 1999 12.3369903564453 2000 12.8894500732422 2001 13.0239601135254 2002 13.2889204025269 2003 13.9986801147461 2004 14.5084295272827 2005 15.2436199188232 2006 17.1726093292236 2007 17.3398399353027 2008 18.9845294952393 2009 21.6961097717285 2010 22.3055191040039 2011 22.8874092102051 2012 23.4304790496826 2013 24.6618194580078 2014 26.3313293457031 2015 26.3471908569336 2016 26.7113800048828 2017 26.8931503295898 2018 26.9975605010986 2019 27.6451892852783 2020 28.1591892242432