Year	gross (GPI)
1991	0.996630012989044
1992	0.983900010585785
1993	0.96126002073288
1994	0.939000010490417
1995	1.05991995334625
1996	1.06005001068115
1997	1.03029000759125
2018	1.00261998176575
2019	1.01073002815247
2020	1.00514996051788
2021	0.993879973888397