Year	%
1971	33.91813
1972	31.01075
1973	36.58641
1974	31.51564
1975	38.81512
1976	49.43559
1977	46.45754
1978	37.87568
1980	45.2779
1989	37.23315
1990	63.66175
1991	41.73508
1996	47.83619
1998	47.60979
1999	47.24771
2000	49.7062
2001	57.64267
2002	56.93293
2003	61.30638
2004	68.34987
2005	70.98655
2006	49.90788
2007	56.31326
2008	56.16118
2009	76.1233
2010	70.0698
2011	61.97104
2012	68.51891
2013	62.00596
2015	56.04456