Year	gross (GPI)
1971	0.729499995708466
1972	0.770820021629334
1973	0.788590013980865
1974	0.806379973888397
1975	0.816209971904755
1976	0.828379988670349
1977	0.83788001537323
1978	0.844359993934631
1979	0.841650009155273
1980	0.849319994449615
1981	0.852649986743927
1982	0.861760020256042
1983	0.908990025520325
1984	0.938099980354309
1985	0.967490017414093
1986	0.989109992980957
1987	0.99506002664566
1988	0.999239981174469
1989	1.01013994216919
1990	1.02781999111176
1991	1.02438998222351
1992	1.03640997409821
1993	1.03960001468658
1994	1.03719997406006
1995	1.02302002906799
1996	1.01893997192383
1997	1.02515995502472
1998	1.0246399641037
1999	1.0246000289917
2000	1.02969002723694
2001	1.05332005023956
2002	1.06584000587463
2003	1.07104003429413
2004	1.06941998004913
2005	1.06912994384766
2006	1.07209002971649
2011	0.998660027980804
2012	1.01332998275757
2013	1.01445996761322
2014	1.00918996334076
2015	1.00213003158569
2016	1.01494002342224
2017	1.01399004459381
2018	1.02155005931854
2019	1.03770005702972