Year % gross 1970 0.2533999979496 1971 0.252829998731613 1972 0.264450013637543 1973 0.284539997577667 1974 0.307909995317459 1975 0.332159996032715 1976 0.376969993114471 1977 0.459160000085831 1978 0.523239970207214 1979 0.652570009231567 1980 0.723420023918152 1981 0.857829988002777 1982 0.934759974479675 1983 0.981880009174347 1984 1.02901995182037 1985 1.13343000411987 1986 1.21896004676819 1987 1.2694000005722 1988 1.26954996585846 1989 1.30175995826721 1990 1.43919003009796 1991 1.58613002300262 1992 1.75460004806519 1993 1.93997001647949 1994 2.14586997032166 1995 2.34381008148193 1996 2.58196997642517 1997 2.84048008918762 1998 3.06159996986389 1999 3.31027007102966 2000 3.79996991157532 2001 4.1361198425293 2002 4.50686979293823 2003 4.84798002243042 2004 5.07281017303467 2005 5.42494010925293 2006 5.48256015777588 2007 5.67609977722168 2008 5.85289001464844 2009 6.04897022247314 2010 6.25971984863281 2011 6.38551998138428 2012 6.71723985671997 2013 7.18726015090942 2014 7.39493989944458 2015 7.55685997009277 2016 7.44323015213013 2017 7.51820993423462 2018 7.7843599319458 2019 8.02795028686523 2020 8.2526798248291