Year	Percent
1991	37.407
1992	38.762
1993	41.606
1994	42.545
1995	43.882
1996	45.499
1997	43.582
1998	44.649
1999	47.173
2000	48.895
2001	47.156
2002	44.496
2003	46.429
2004	47.834
2005	48.93
2006	47.852
2007	46.463
2008	48.761
2009	54.34
2010	54.75
2011	55.034
2012	54.871
2013	54.28
2014	54.55
2015	54.457
2016	54.347
2017	54.532
2018	54.965
2019	55.397
2020	55.832
2021	56.229
2022	56.609