Year	% gross
1970	18.4148807525635
1971	18.5572490692139
1972	18.9205894470215
1973	19.2348709106445
1974	19.3111801147461
1975	19.7446098327637
1976	20.2591400146484
1977	20.9263401031494
1978	21.8287506103516
1979	22.6772193908691
1980	23.2523403167725
1981	23.8291301727295
1982	24.3822898864746
1983	24.6312599182129
1984	24.5312805175781
1985	24.1498203277588
1986	23.7563095092773
1987	23.4630794525146
1988	23.4128093719482
1989	22.8838005065918
1990	22.4213695526123
1991	22.2742290496826
1992	21.7717208862305
1993	21.6458797454834
1994	21.9708995819092
1995	22.5182399749756
1996	22.5189800262451
1997	22.6100997924805
1998	23.2383193969727
1999	23.6412391662598
2000	24.1200504302979
2001	25.040340423584
2002	25.7967090606689
2003	27.496000289917
2004	28.8959102630615
2005	29.9634895324707
2006	31.6883907318115
2007	32.6602401733398
2008	34.4722900390625
2009	35.8523406982422
2010	37.0476989746094
2011	38.0969886779785
2012	39.0395317077637
2013	38.3985900878906
2014	38.719051361084
2015	38.7585182189941
2016	39.1743316650391
2017	39.6477813720703
2018	39.9431381225586
2019	39.9322090148926
2020	40.2920188903809