Year	Percent
1991	47.904
1992	48.791
1993	48.774
1994	49.188
1995	48.781
1996	46.446
1997	43.457
1998	42.45
1999	40.416
2000	38.494
2001	36.964
2002	33.199
2003	31.809
2004	30.47
2005	28.405
2006	27.443
2007	28.22
2008	28.922
2009	27.869
2010	28.61
2011	27.075
2012	27.638
2013	27.074
2014	26.674
2015	29.629
2016	27.365
2017	27.584
2018	27.766
2019	27.079
2020	26.944
2021	26.725
2022	26.428