Year	Percent
1990	35.107
1991	35.172
1992	35.287
1993	35.463
1994	35.722
1995	35.431
1996	35.13
1997	34.83
1998	34.532
1999	34.238
2000	33.951
2001	34.501
2002	35.058
2003	35.624
2004	36.199
2005	36.784
2006	35.032
2007	33.334
2008	31.69
2009	30.097
2010	28.555
2011	27.67
2012	26.809
2013	26.961
2014	27.117
2015	27.267
2016	27.448
2017	27.209
2018	26.968
2019	26.726
2020	26.482
2021	26.235
2022	25.988
2023	25.741
2024	25.496
2025	25.253
2026	25.011
2027	24.774
2028	24.535
2029	24.291
2030	24.036