Year	Percent
1990	41.184
1991	40.944
1992	40.62
1993	40.238
1994	39.846
1995	39.458
1996	39.267
1997	39.116
1998	38.973
1999	38.813
2000	38.648
2001	38.472
2002	38.294
2003	38.121
2004	37.967
2005	37.873
2006	37.696
2007	37.562
2008	37.462
2009	37.294
2010	37.131
2011	36.895
2012	36.595
2013	36.298
2014	35.972
2015	35.674
2016	35.269
2017	35.161
2018	35.064
2019	34.96
2020	34.836
2021	34.694
2022	34.537
2023	34.362
2024	34.168
2025	33.956
2026	33.729
2027	33.489
2028	33.239
2029	32.985
2030	32.733