Year	Percent
1991	48.694
1992	48.547
1993	48.092
1994	48.694
1995	47.814
1996	48.222
1997	48.749
1998	49.942
1999	51.568
2000	51.614
2001	53.735
2002	54.274
2003	56.667
2004	56.729
2005	53.753
2006	50.608
2007	48.002
2008	44.862
2009	41.071
2010	38.403
2011	35.293
2012	30.814
2013	29.185
2014	27.123
2015	32.07
2016	32.725
2017	37.561
2018	38.48
2019	39.33
2020	40.214
2021	41.078
2022	41.948