Year	gross (GPI)
1970	0.602270007133484
1971	0.590229988098145
1972	0.5625
1973	0.537129998207092
1974	0.535669982433319
1975	0.532329976558685
1976	0.535390019416809
1977	0.51936000585556
1978	0.500739991664886
1979	0.479620009660721
1980	0.464659988880157
1981	0.456800013780594
1982	0.451620012521744
1983	0.451059997081757
1984	0.449730008840561
1985	0.429939985275269
1986	0.456030011177063
1987	0.481330007314682
1988	0.462240010499954
1989	0.449530005455017
1990	0.460640013217926
1991	0.468019992113113
1992	0.480329990386963
1993	0.490979999303818
1994	0.504360020160675
1995	0.518760025501251
1996	0.536360025405884
1997	0.553040027618408
1998	0.573650002479553
1999	0.595759987831116
2000	0.600679993629456
2001	0.596580028533936
2002	0.600579977035522
2003	0.592939972877502
2004	0.607879996299744
2005	0.611410021781921
2006	0.623019993305206
2007	0.619549989700317
2008	0.61751002073288
2009	0.610210001468658
2010	0.620899975299835
2011	0.60878998041153
2012	0.629350006580353
2013	0.635029971599579
2014	0.629670023918152
2015	0.637489974498749
2016	0.651830017566681
2017	0.657320022583008
2018	0.667630016803741
2019	0.676050007343292
2020	0.688570022583008
2021	0.688510000705719