Year	Percent
1990	35.866
1991	38.257
1992	40.663
1993	43.05
1994	45.388
1995	45.14
1996	45.004
1997	44.828
1998	44.587
1999	44.376
2000	44.263
2001	44.43
2002	44.692
2003	45.006
2004	45.303
2005	45.475
2006	45.599
2007	45.691
2008	45.582
2009	45.485
2010	45.4
2011	45.359
2012	45.345
2013	45.379
2014	45.304
2015	45.172
2016	45.146
2017	45.149
2018	45.137
2019	45.092
2020	45.012
2021	44.971
2022	44.897
2023	44.805
2024	44.731
2025	44.684
2026	44.73
2027	44.803
2028	44.885
2029	44.962
2030	45.029