Year	% of total
1990	69.05831786656248
1991	63.03720577069096
1992	65.58868669151502
1993	65.52160493827161
1994	65.9074074074074
1995	62.887225896275666
1996	56.47152302846278
1997	62.902149245761585
1998	63.68757934828607
1999	56.74947620472912
2000	62.77973052138254
2001	62.22317107884998
2002	64.343981745579
2003	69.86936605779562
2004	68.29061189831768
2005	64.27043921697647
2006	68.72892738685891
2007	70.05198358413132
2008	72.43897803480763
2009	71.32214533789337
2010	67.05501964032814
2011	75.70218809173154
2012	72.8041801443145
2013	73.13839957172355
2014	66.2739939006159
2015	72.42984439420135