Year	Percent
1990	39.93
1991	40.575
1992	41.369
1993	42.193
1994	43.178
1995	44.384
1996	44.563
1997	44.733
1998	44.919
1999	45.148
2000	45.438
2001	45.428
2002	45.682
2003	46.217
2004	46.98
2005	47.736
2006	48.198
2007	48.666
2008	49.068
2009	49.186
2010	49.491
2011	49.996
2012	50.337
2013	50.378
2014	50.271
2015	50.095
2016	49.243
2017	48.695
2018	48.229
2019	47.835
2020	47.488
2021	46.82
2022	46.215
2023	45.697
2024	45.279
2025	44.953
2026	44.531
2027	44.178
2028	43.916
2029	43.764
2030	43.723