Year	Percent
1990	29.18
1991	29.421
1992	29.815
1993	30.214
1994	30.755
1995	31.258
1996	31.557
1997	31.961
1998	32.489
1999	33.101
2000	33.718
2001	34.068
2002	34.619
2003	35.355
2004	36.232
2005	37.173
2006	38.562
2007	40.109
2008	41.776
2009	42.558
2010	42.916
2011	42.668
2012	42.531
2013	42.345
2014	42.077
2015	41.793
2016	41.251
2017	40.907
2018	40.612
2019	40.349
2020	40.091
2021	39.593
2022	39.134
2023	38.735
2024	38.407
2025	38.14
2026	37.714
2027	37.367
2028	37.103
2029	36.915
2030	36.781