Year % gross 1970 8.61816024780273 1971 9.00870990753174 1972 10.1928596496582 1973 10.7033195495605 1974 10.8304901123047 1975 11.8933801651001 1976 11.7549600601196 1977 11.286319732666 1978 10.7479000091553 1979 10.8651103973389 1981 11.2714700698853 1982 11.2794399261475 1984 12.0831298828125 1986 12.2304000854492 1987 13.0785598754883 1988 13.2802000045776 1989 13.3125801086426 1990 12.7669897079468 1991 12.9777898788452 1992 12.7590198516846 1993 13.7518100738525 1994 14.2420902252197 1995 13.0271196365356 1998 19.8210601806641 2012 37.1345100402832 2018 44.4107818603516