Year	gross (GPI)
1971	0.346909999847412
1972	0.357630014419556
1973	0.385250002145767
1974	0.388350009918213
1975	0.396450012922287
1976	0.408499985933304
1977	0.400510013103485
1978	0.445650011301041
1979	0.458299994468689
1980	0.46068999171257
1981	0.468030005693436
1982	0.476209998130798
1983	0.462520003318787
1984	0.463220000267029
1985	0.47189000248909
1986	0.487489998340607
1987	0.488029986619949
1988	0.498149991035461
1989	0.494610011577606
1990	0.497209995985031
2006	0.783940017223358
2007	0.804989993572235
2008	0.811029970645905
2009	0.830179989337921
2010	0.821619987487793
2011	0.81726998090744
2012	0.817430019378662
2013	0.814499974250793
2014	0.8298100233078
2015	0.832499980926514
2016	0.839510023593903
2017	0.845960021018982
2018	0.848890006542206
2019	0.87747997045517