Year % gross 1975 8.67216014862061 1998 21.1123294830322 1999 31.0614490509033 2004 25.1977806091309 2012 36.9199981689453 2014 41.9436302185059 2015 47.3548393249512 2018 45.4958686828613 2019 49.8568496704102 2020 50.5761299133301