Year	Percent
1990	45.08
1991	44.848
1992	44.498
1993	44.183
1994	43.71
1995	43.227
1996	42.785
1997	42.45
1998	42.559
1999	42.103
2000	40.803
2001	39.813
2002	37.804
2003	35.931
2004	34.154
2005	32.447
2006	31.035
2007	29.806
2008	28.764
2009	27.886
2010	27.132
2011	26.803
2012	26.498
2013	26.255
2014	25.97
2015	25.772
2016	25.657
2017	25.425
2018	25.211
2019	24.98
2020	24.712
2021	24.47
2022	24.2
2023	23.917
2024	23.652
2025	23.423
2026	23.277
2027	23.174
2028	23.087
2029	22.974
2030	22.808