Year	% gross
1971	18.2722301483154
1972	19.6234397888184
1973	22.238109588623
1975	23.5583591461182
1977	26.8058605194092
1978	26.1134796142578
1979	29.3023204803467
1980	30.0046405792236
1981	29.7001705169678
1982	32.6891708374023
1983	33.1576881408691
1984	33.6662216186523
1986	33.4643287658691
1987	33.3135795593262
1988	31.5543193817139
1989	30.7423706054688
1990	30.4202404022217
1991	31.9885902404785
1993	35.0870513916016
1995	36.9994316101074
1996	39.3073806762695
1998	45.1618118286133
1999	47.2852783203125
2000	48.2686614990234
2001	50.4822311401367
2002	54.9123497009277
2003	54.520580291748
2004	53.9075012207031
2005	54.8960990905762
2006	54.3149490356445
2007	57.1039505004883
2008	56.4970207214355
2009	59.0821189880371
2010	61.8530311584473
2011	61.9456214904785
2012	63.5912704467773
2013	62.0624198913574
2014	62.1056289672852
2015	60.8227882385254
2016	60.4474411010742
2017	59.0658683776855
2018	57.3934288024902
2019	55.9445381164551
2020	56.4272193908691
2021	58.9942817687988