Year	% gross
1970	18.9608497619629
1971	18.9859199523926
1972	19.3761596679688
1973	19.5652694702148
1974	19.6732692718506
1975	20.4252300262451
1976	21.0386295318604
1977	21.6024799346924
1978	22.4000606536865
1979	23.2256202697754
1980	24.0076007843018
1981	24.5011692047119
1982	25.4262790679932
1983	26.0681304931641
1984	26.7755107879639
1985	27.5451507568359
1986	27.6257190704346
1987	27.5812892913818
1988	27.3937892913818
1989	26.8216590881348
1990	26.6659202575684
1991	26.9392395019531
1992	26.4203205108643
1993	26.5719108581543
1994	27.0411701202393
1995	27.5254306793213
1996	27.8591003417969
1997	28.0796909332275
1998	29.0462398529053
1999	29.4916191101074
2000	29.8463897705078
2001	31.0944194793701
2002	31.8691902160645
2003	32.6427001953125
2004	34.4579391479492
2005	35.6052284240723
2006	37.3583297729492
2007	39.1506690979004
2008	40.5510406494141
2009	41.7092094421387
2010	42.5904083251953
2011	43.0487518310547
2012	44.0202102661133
2013	44.6487617492676
2014	45.431640625
2015	45.528148651123
2016	45.3768615722656
2017	45.6563987731934
2018	45.760311126709
2019	46.1482200622559
2020	46.4435615539551