Year	Percent
1960	21.22556
1961	22.02375
1962	18.46667
1963	18.47222
1964	10.34535
1965	8.3061
1966	7.04828
1967	9.758
1968	6.75566
1969	9.32793
1970	20.91636
1993	97.84492
1994	89.11743
1995	100.95948
1996	74.48262
1997	62.77819
1998	83.50124
1999	42.06684
2000	53.95034
2001	49.16828
2002	47.48655
2003	43.10721
2004	42.77507
2005	35.56682
2006	29.08086
2007	34.73901
2008	31.78518
2009	28.71197
2010	34.88005
2011	31.54427
2012	31.04511
2013	26.52516
2014	21.75073
2015	16.75502
2016	16.02761
2017	16.86614
2018	13.59681
2019	14.72176
2020	21.33341
2021	21.31044