Year gross (GPI) 1988 0.817589998245239 1989 0.832499980926514 1990 0.790910005569458 1991 0.841080009937286 1992 0.877120018005371 1993 0.865339994430542 1994 0.925679981708527 2012 1.29364001750946 2013 1.29782998561859 2014 1.2974499464035 2015 1.30209004878998 2016 1.30541002750397 2017 1.30654001235962 2018 1.32193994522095 2019 1.33575999736786 2020 1.36945998668671 2021 1.38700997829437