Year	Percent
1981	12.24041
1982	13.50269
1983	14.99073
1984	18.30836
1985	18.22764
1986	18.02043
1987	20.55211
1988	23.37165
1989	21.2756
1990	21.55626
1991	20.88528
1992	20.32116
1993	23.49113
1994	25.17385
1995	25.48651
1996	26.19916
1997	27.41665
1998	27.90837
1999	26.02849
2000	21.35724
2001	24.47535
2002	36.96508
2003	33.82706
2004	27.23045
2005	26.08928
2006	24.73499
2007	24.66258
2008	25.27975
2009	26.74885
2010	23.8937
2011	22.23471
2012	21.85996
2013	20.75862
2014	19.99025
2015	20.63189
2016	20.98311
2017	20.84657
2018	21.20377
2019	21.9063
2020	24.14331
2021	23.35706
2022	23.69187