Year	% gross
1971	2.25336003303528
1972	2.35838007926941
1973	2.36668992042542
1974	2.41480994224548
1975	2.48352003097534
1976	4.08440017700195
1977	4.18707990646362
1978	4.20295000076294
1979	4.00633001327515
1980	4.31577014923096
1981	4.25598001480103
1982	4.3406400680542
1983	3.99334001541138
1984	3.93301010131836
1985	4.69681978225708
1986	5.71790981292725
1987	5.91953992843628
1988	5.85400009155273
1989	6.69195985794067
1991	6.55406999588013
1992	6.6472601890564
1993	7.09244012832642
1999	5.6235499382019
2000	5.55650997161865
2001	6.03922986984253
2002	8.33351039886475
2003	8.45785999298096
2004	11.5449304580688
