Year	Percent
1990	41.606
1991	41.866
1992	42.143
1993	42.478
1994	42.854
1995	43.248
1996	43.536
1997	43.817
1998	44.094
1999	44.411
2000	44.766
2001	44.98
2002	45.222
2003	45.473
2004	45.692
2005	45.924
2006	46.134
2007	46.354
2008	47.925
2009	46.293
2010	44.729
2011	45.198
2012	45.419
2013	46.386
2014	46.613
2015	47.801
2016	47.787
2017	47.848
2018	47.901
2019	47.945
2020	47.979
2021	47.989
2022	47.991
2023	47.984
2024	47.967
2025	47.938
2026	47.887
2027	47.827
2028	47.762
2029	47.703
2030	47.655