Year	Percent
1990	47.297
1991	47.413
1992	47.816
1993	47.792
1994	49.811
1995	49.782
1996	50.009
1997	49.691
1998	50.025
1999	50.143
2000	49.875
2001	49.351
2002	48.783
2003	48.365
2004	47.998
2005	46.363
2006	44.678
2007	42.994
2008	41.295
2009	39.567
2010	38.895
2011	39.171
2012	38.018
2013	38.503
2014	38.259
2015	41.257
2016	39.975
2017	39.446
2018	38.896
2019	38.336
2020	37.774
2021	37.188
2022	36.605
2023	36.026
2024	35.446
2025	34.862
2026	34.266
2027	33.663
2028	33.051
2029	32.43
2030	31.798