Year	gross (GPI)
1971	0.260490000247955
1972	0.275110006332397
1973	0.301759988069534
1974	0.307680010795593
1975	0.325599998235703
1976	0.321469992399216
1977	0.33228000998497
1978	0.337260007858276
1979	0.374370008707047
1980	0.366169989109039
1981	0.367549985647202
1982	0.369520008563995
1983	0.351969987154007
1984	0.353199988603592
1985	0.363519996404648
1986	0.393040001392365
1987	0.402570009231567
1988	0.411980003118515
1989	0.417959988117218
1990	0.417540013790131
1991	0.477770000696182
1992	0.501649975776672
2006	0.776939988136292
2007	0.760349988937378
2008	0.760930001735687
2009	0.794470012187958
2010	0.772909998893738
2011	0.753000020980835
2012	0.735589981079102
2013	0.732100009918213
2014	0.791769981384277
2015	0.794000029563904
2016	0.811999976634979
2017	0.81291002035141
2018	0.852389991283417
2019	0.868359982967377