Year % gross 1971 6.77091979980469 1972 6.36908006668091 1973 6.49980020523071 1974 7.14283990859985 1975 8.03649997711182 1976 9.0334997177124 1977 10.5183897018433 1978 11.8944902420044 1979 12.7485399246216 1980 14.0102701187134 1981 15.0849304199219 1982 15.3142099380493 1983 14.88148021698 1984 14.0019397735596 1985 13.3269395828247 1986 13.0928802490234 1987 13.4117603302002 1988 13.8540096282959 1989 14.3045301437378 1990 14.2474098205566 1991 14.5435199737549 1992 13.2547597885132 1993 12.8920001983643 1994 18.6427097320557 1995 19.644510269165 1996 20.1621894836426 1997 22.5634307861328 1998 23.3425903320312 1999 26.4795093536377 2000 30.2823696136475 2001 32.800910949707 2002 38.5895690917969 2003 40.5895385742188 2004 47.5738410949707 2005 52.747428894043 2006 54.833179473877 2007 60.6281700134277 2008 65.9205017089844 2009 71.3405609130859 2010 75.7174911499023 2011 78.233642578125 2012 78.3601303100586 2013 77.8659515380859 2014 78.8316879272461 2015 78.8992462158203 2016 79.1647186279297 2017 79.4584579467773 2018 78.0667419433594 2019 78.2053298950195 2020 78.7804183959961 2021 80.7192001342773