Year	Percent
1990	41.742
1991	41.928
1992	42.161
1993	42.457
1994	42.842
1995	42.629
1996	42.411
1997	42.192
1998	41.969
1999	41.743
2000	41.515
2001	42.242
2002	42.97
2003	43.698
2004	44.426
2005	45.155
2006	43.191
2007	41.251
2008	39.34
2009	37.466
2010	35.633
2011	34.711
2012	33.809
2013	34.052
2014	34.299
2015	34.532
2016	34.787
2017	34.571
2018	34.356
2019	34.142
2020	33.925
2021	33.706
2022	33.484
2023	33.261
2024	33.035
2025	32.807
2026	32.576
2027	32.342
2028	32.106
2029	31.868
2030	31.627