Year	% gross
1977	26.7144908905029
1978	24.9125308990479
1979	23.8687191009521
1980	17.7723903656006
1981	15.8055295944214
1982	14.7000999450684
1983	11.1857595443726
1984	12.8857698440552
1985	14.0448398590088
1986	16.0913391113281
1987	17.7493095397949
1988	19.1994495391846
1995	14.3343200683594