Year	Percent
1991	40.863
1992	41.432
1993	40.943
1994	40.924
1995	41.374
1996	41.499
1997	43.188
1998	41.964
1999	43.59
2000	44.02
2001	42.471
2002	41.412
2003	41.239
2004	41.647
2005	41.489
2006	41.301
2007	41.863
2008	42.337
2009	42.661
2010	40.782
2011	40.674
2012	41.233
2013	40.488
2014	39.446
2015	38.162
2016	37.691
2017	38.322
2018	39.267
2019	38.246
2020	37.839
2021	37.04
2022	36.416