Year	% gross
1970	7.6388897895813
1971	7.61919021606445
1972	7.61149978637695
1973	7.57630014419556
1974	7.51704978942871
1975	7.52089977264404
1976	7.58629989624023
1977	7.85372018814087
1978	8.09224033355713
1979	8.23585033416748
1980	8.33143043518066
1981	8.43609046936035
1982	8.46310997009277
1983	8.46055030822754
1984	8.53232955932617
1985	8.60673046112061
1986	8.69431972503662
1987	8.72043991088867
1988	8.80286979675293
1989	8.86783027648926
1990	8.88393020629883
1991	8.79885005950928
1992	8.65058994293213
1993	8.5649299621582
1994	8.38016033172607
1995	8.51292991638184
1996	8.5826997756958
1997	8.80245971679688
1998	9.08460998535156
1999	9.46621036529541
2000	9.83683967590332
2001	10.7011003494263
2002	11.4490203857422
2003	12.0081195831299
2004	12.5866603851318
2005	13.4811496734619
2006	14.1866903305054
2007	14.6946001052856
2008	15.3384399414062
2009	15.5774202346802
2010	15.6905002593994
2011	15.787859916687
2012	15.6455297470093
2013	15.5487899780273
2014	15.7469100952148
2015	15.314169883728
2016	14.9805097579956
2017	14.9949998855591
2018	14.978569984436
2019	14.8640899658203