Year	Percent
1991	14.704
1992	15.169
1993	16.248
1994	16.953
1995	17.071
1996	17.276
1997	16.573
1998	12.961
1999	8.946
2000	12.866
2001	16.515
2002	19.609
2003	22.272
2004	25.772
2005	28.486
2006	32.857
2007	37.697
2008	48.542
2009	47.953
2010	48.068
2011	49.264
2012	50.087
2013	50.85
2014	50.691
2015	51.313
2016	51.576
2017	51.717
2018	52.081
2019	52.168
2020	52.319
2021	52.412
2022	52.522