Year % gross 1970 3.47561001777649 1973 3.52488994598389 1974 3.5048201084137 1975 3.52179002761841 1976 4.15931987762451 1977 4.27017021179199 1978 4.35075998306274 1979 4.44454002380371 1980 4.79601001739502 1981 5.0842399597168 1982 7.55113983154297 1983 6.68969011306763 1984 7.84640979766846 1985 8.3954496383667 1986 9.69324016571045 1987 10.6993503570557 1988 11.2913103103638 1990 10.9507598876953 1991 10.2611598968506 1992 10.0543298721313 1993 10.0059995651245 1994 10.2789602279663 1995 10.6396198272705 1997 10.1858901977539 2004 19.0221099853516 2007 23.8660507202148 2010 26.3339996337891 2011 25.2759990692139 2012 25.378999710083 2013 26.9979991912842 2014 26.9400005340576 2016 26.3269996643066 2017 24