Year	Percent
1990	51.905
1991	52.139
1992	52.22
1993	52.31
1994	52.564
1995	52.279
1996	51.717
1997	51.501
1998	51.64
1999	51.987
2000	51.63
2001	51.235
2002	50.932
2003	51.048
2004	50.638
2005	50.773
2006	50.623
2007	49.888
2008	49.349
2009	49.509
2010	49.232
2011	49.432
2012	50.066
2013	50.988
2014	50.968
2015	51.422
2016	52.066
2017	51.958
2018	51.844
2019	51.715
2020	51.561
2021	51.365
2022	51.138
2023	50.896
2024	50.671
2025	50.484
2026	50.343
2027	50.251
2028	50.182
2029	50.089
2030	49.94