Year	Percent
1990	52.48
1991	52.324
1992	52.132
1993	51.909
1994	51.684
1995	51.488
1996	51.337
1997	52.541
1998	53.072
1999	51.786
2000	51.245
2001	50.937
2002	51.675
2003	50.276
2004	52.808
2005	52.85
2006	53.258
2007	53.487
2008	53.628
2009	53.526
2010	53.183
2011	52.354
2012	52.318
2013	51.793
2014	52.346
2015	52.034
2016	52.073
2017	51.734
2018	51.377
2019	50.993
2020	50.574
2021	50.137
2022	49.68
2023	49.209
2024	48.735
2025	48.268
2026	47.83
2027	47.406
2028	46.998
2029	46.606
2030	46.228