Year	Percent
1991	38.512
1992	30.197
1993	31.36
1994	32.484
1995	31.24
1996	28.94
1997	33.951
1998	32.761
1999	33.915
2000	33.99
2001	33.807
2002	33.767
2003	33.3
2004	33.792
2005	30.749
2006	32.782
2007	32.23
2008	29.672
2009	28.7
2010	28.169
2011	27.598
2012	27.353
2013	27.118
2014	27.12
2015	26.927
2016	25.883
2017	25.303
2018	25.274
2019	25.214
2020	25.166
2021	25.116
2022	25.066