Year	Percent
1991	51.8
1992	53.168
1993	53.798
1994	52.359
1995	51.259
1996	49.309
1997	50.025
1998	49.639
1999	44.753
2000	45.904
2001	46.881
2002	42.838
2003	41.98
2004	44.88
2005	47.35
2006	50.748
2007	50.58
2008	50.228
2009	48.884
2010	47.192
2011	47.048
2012	46.307
2013	45.526
2014	45.449
2015	44.792
2016	43.213
2017	42.096
2018	41.461
2019	41.108
2020	40.699
2021	40.307
2022	39.909