Year	Percent
1990	40.817
1991	40.938
1992	40.744
1993	40.677
1994	40.507
1995	40.424
1996	40.264
1997	40.079
1998	39.891
1999	39.708
2000	39.538
2001	39.519
2002	39.514
2003	39.505
2004	39.472
2005	39.402
2006	39.241
2007	39.057
2008	39.643
2009	40.244
2010	40.878
2011	41.569
2012	42.281
2013	42.999
2014	43.703
2015	43.636
2016	43.622
2017	43.693
2018	43.739
2019	43.76
2020	43.759
2021	43.772
2022	43.761
2023	43.739
2024	43.732
2025	43.756
2026	43.846
2027	43.968
2028	44.111
2029	44.257
2030	44.398