Year	Percent
1991	18.266
1992	19.031
1993	18.764
1994	19.175
1995	19.139
1996	18.997
1997	19.825
1998	19.562
1999	20.336
2000	20.622
2001	21.158
2002	20.463
2003	20.1
2004	19.447
2005	20.499
2006	20.211
2007	25.208
2008	21.17
2009	20.769
2010	21.874
2011	21.614
2012	22.429
2013	23.343
2014	23.228
2015	23.191
2016	23.409
2017	23.356
2018	23.224
2019	23.454
2020	23.606
2021	23.74
2022	23.868