Year	Percent
1991	19.616
1992	20.269
1993	19.954
1994	20.04
1995	20.454
1996	20.899
1997	21.005
1998	21.268
1999	21.607
2000	21.774
2001	22.371
2002	22.627
2003	22.74
2004	23.1
2005	23.056
2006	23.244
2007	24.878
2008	25.314
2009	24.946
2010	25.133
2011	26.274
2012	26.071
2013	25.946
2014	25.798
2015	25.671
2016	25.895
2017	25.992
2018	26.243
2019	26.495
2020	26.767
2021	27.066
2022	27.408