Year	Percent
1990	36.059
1991	34.114
1992	35.398
1993	35.456
1994	36.196
1995	36.939
1996	38.232
1997	38.299
1998	39.889
1999	40.892
2000	40.849
2001	39.888
2002	40.612
2003	41.266
2004	42.642
2005	42.712
2006	43.114
2007	43.097
2008	43.138
2009	44.176
2010	44.75
2011	44.568
2012	44.875
2013	44.722
2014	44.851
2015	45.474
2016	45.702
2017	45.5
2018	45.285
2019	45.045
2020	44.771
2021	44.488
2022	44.185
2023	43.872
2024	43.563
2025	43.263
2026	42.982
2027	42.72
2028	42.468
2029	42.218
2030	41.96