Year	Percent
1990	59.783
1991	59.723
1992	57.602
1993	55.187
1994	51.445
1995	51.568
1996	52.304
1997	51.809
1998	51.228
1999	51.684
2000	52.305
2001	52.855
2002	52.337
2003	52.594
2004	52.515
2005	51.265
2006	50.675
2007	50.482
2008	50.891
2009	50.184
2010	50.637
2011	50.21
2012	50.727
2013	51.071
2014	51.119
2015	51.998
2016	52.653
2017	52.453
2018	52.239
2019	52.004
2020	51.745
2021	51.46
2022	51.156
2023	50.843
2024	50.544
2025	50.275
2026	50.05
2027	49.862
2028	49.697
2029	49.533
2030	49.351