Year	gross (GPI)
1970	0.60615998506546
1971	0.605960011482239
1972	0.621020019054413
1973	0.619889974594116
1974	0.619849979877472
1975	0.625320017337799
1976	0.631929993629456
1977	0.645510017871857
1978	0.65336000919342
1979	0.656570017337799
1980	0.668290019035339
1981	0.6839399933815
1982	0.704240024089813
1983	0.694850027561188
1984	0.715449988842011
1985	0.712069988250732
1986	0.722530007362366
1987	0.729770004749298
1988	0.743300020694733
1989	0.750280022621155
1990	0.757539987564087
1991	0.769029974937439
1992	0.776510000228882
1993	0.782509982585907
1994	0.78754997253418
1995	0.790870010852814
1996	0.795239984989166
1997	0.804780006408691
1998	0.813059985637665
1999	0.829469978809357
2000	0.839690029621124
2001	0.845920026302338
2002	0.851220011711121
2003	0.858810007572174
2004	0.851639986038208
2005	0.871810019016266
2006	0.880919992923737
2007	0.887589991092682
2008	0.897170007228851
2009	0.902800023555756
2010	0.914929986000061
2011	0.922950029373169
2012	0.927110016345978
2013	0.929480016231537
2014	0.933279991149902
2015	0.943359971046448
2016	0.944790005683899
2017	0.948430001735687
2018	0.948199987411499
2019	0.950510025024414
2020	0.955039978027344