Year	Percent
1970	67.56437
1971	68.54848
1975	75.61203
1976	75.67845
1996	91.9393
1997	90.12609
1998	98.32889
1999	97.60886
2000	98.09367
2001	97.5468
2002	101.43944
2003	99.50121
2004	98.20293
2005	96.36109
2006	99.01243
2007	101.74881
2008	105.13899
2009	105.23676
2010	105.28634
2011	104.71846
2012	103.65624
2013	101.41809
2014	102.39483
2015	102.05138