Year	Percent
1990	35.461
1991	35.687
1992	36.075
1993	36.407
1994	37.028
1995	37.616
1996	38.151
1997	38.723
1998	39.329
1999	39.952
2000	40.571
2001	41.134
2002	41.743
2003	42.385
2004	43.032
2005	43.652
2006	45.313
2007	46.944
2008	48.534
2009	49.298
2010	49.199
2011	48.729
2012	48.533
2013	48.33
2014	48.033
2015	47.728
2016	47.333
2017	47.121
2018	46.924
2019	46.748
2020	46.592
2021	46.344
2022	46.136
2023	45.975
2024	45.865
2025	45.798
2026	45.655
2027	45.573
2028	45.554
2029	45.597
2030	45.693