Year	Percent
1990	37.268
1991	37.993
1992	38.718
1993	39.35
1994	38.773
1995	38.177
1996	37.596
1997	37.038
1998	36.504
1999	35.989
2000	35.475
2001	34.912
2002	34.314
2003	34.039
2004	34.168
2005	34.086
2006	34.767
2007	35.612
2008	36.109
2009	36.601
2010	37.041
2011	37.821
2012	38.516
2013	39.203
2014	39.762
2015	40.218
2016	40.558
2017	40.712
2018	40.85
2019	40.972
2020	41.083
2021	41.201
2022	41.309
2023	41.401
2024	41.47
2025	41.516
2026	41.563
2027	41.591
2028	41.605
2029	41.611
2030	41.617