Year	Percent
1991	32.997
1992	33.293
1993	33.346
1994	33.133
1995	33.147
1996	34.353
1997	33.38
1998	34.787
1999	34.796
2000	35.176
2001	35.018
2002	35.798
2003	36.103
2004	36.521
2005	38.113
2006	37.466
2007	39.143
2008	40.457
2009	41.496
2010	42.799
2011	44.203
2012	45.287
2013	46.168
2014	46.946
2015	48.292
2016	50.022
2017	49.977
2018	50.822
2019	51.814
2020	52.675
2021	53.453
2022	54.288