Year	Percent
1991	44.806
1992	44.878
1993	45.48
1994	45.023
1995	45.453
1996	44.772
1997	44.972
1998	45.163
1999	45.249
2000	43.604
2001	44.347
2002	45.067
2003	45.205
2004	46.103
2005	46.922
2006	47.577
2007	47.91
2008	47.663
2009	47.591
2010	48.057
2011	48.073
2012	48.629
2013	49.353
2014	49.568
2015	49.922
2016	49.91
2017	49.938
2018	50.51
2019	51.142
2020	51.728
2021	52.424
2022	52.979