Year	Percent
1990	37.631
1991	40.123
1992	42.614
1993	45.067
1994	47.435
1995	47.209
1996	47.12
1997	46.975
1998	46.731
1999	46.51
2000	46.394
2001	46.588
2002	46.884
2003	47.246
2004	47.602
2005	47.787
2006	47.935
2007	48.061
2008	47.896
2009	47.742
2010	47.59
2011	47.541
2012	47.532
2013	47.613
2014	47.531
2015	47.368
2016	47.311
2017	47.298
2018	47.274
2019	47.224
2020	47.152
2021	47.143
2022	47.11
2023	47.065
2024	47.031
2025	47.02
2026	47.11
2027	47.221
2028	47.341
2029	47.46
2030	47.574