Year	Percent
1991	27.037
1992	26.718
1993	26.857
1994	26.845
1995	28.04
1996	29.231
1997	26.321
1998	26.813
1999	26.489
2000	26.623
2001	27.996
2002	30.318
2003	30.534
2004	32.449
2005	33.197
2006	34.865
2007	34.709
2008	34.739
2009	35.651
2010	35.079
2011	36.645
2012	36.55
2013	36.807
2014	36.95
2015	39.413
2016	39.813
2017	40.722
2018	41.836
2019	42.466
2020	43.177
2021	43.493
2022	43.85