Year	Percent
1990	20.007
1991	20.857
1992	21.134
1993	21.428
1994	21.961
1995	21.947
1996	22.506
1997	22.945
1998	23.383
1999	23.847
2000	24.409
2001	24.776
2002	25.175
2003	26.037
2004	26.609
2005	27.444
2006	27.979
2007	28.481
2008	28.791
2009	28.924
2010	29.327
2011	26.247
2012	28.269
2013	26.995
2014	25.872
2015	25.765
2016	25.809
2017	25.814
2018	25.798
2019	25.764
2020	25.714
2021	25.654
2022	25.582
2023	25.499
2024	25.409
2025	25.312
2026	25.216
2027	25.116
2028	25.017
2029	24.925
2030	24.842