Year % gross 1970 6.61239004135132 1971 6.61276006698608 1972 6.67011022567749 1973 6.80182981491089 1974 6.99903011322021 1975 7.26990985870361 1976 7.57823991775513 1977 7.66379976272583 1978 7.88689994812012 1979 8.35317039489746 1980 8.7628698348999 1981 9.15707969665527 1982 9.05070018768311 1983 9.13945007324219 1984 9.22338008880615 1985 9.209059715271 1986 9.52359962463379 1987 9.78557014465332 1988 9.49090003967285 1989 9.50957012176514 1990 9.53324031829834 1991 9.50222015380859 1992 9.45040035247803 1993 9.49824047088623 1994 9.99536037445068 1995 10.4689502716064 1996 11.2369403839111 1997 11.9329700469971 1998 12.6469402313232 1999 13.4077501296997 2000 14.1913204193115 2001 15.0492095947266 2002 16.0420398712158 2003 17.273250579834 2004 18.1925392150879 2005 18.9069499969482 2006 19.8962898254395 2007 20.9119491577148 2008 22.0287990570068 2009 22.9628505706787 2010 24.3938293457031 2011 26.303539276123 2012 27.4292392730713 2013 28.0596904754639 2014 30.8093700408936 2015 32.1640815734863 2016 32.6942291259766 2017 33.1302185058594 2018 33.4923896789551 2019 34.2664184570312 2020 35.4901390075684 2021 37.0829200744629 2022 38.407299041748