Year	% of total
1990	93.52393516481432
1991	92.62683952579884
1992	87.77939668771695
1993	82.00145465444206
1994	71.09036609173498
1995	64.67421508159042
1996	68.08947637764004
1997	69.24585569421002
1998	70.77945339198688
1999	63.080876851558244
2000	62.78335225834386
2001	60.34194235916289
2002	65.88786628845591
2003	65.04947449948591
2004	67.12009191530886
2005	66.02258082188162
2006	66.59071260229518
2007	70.29172581842731
2008	74.40930312948022
2009	72.98543957748807
2010	70.51697531144437
2011	70.1008025476591
2012	73.86900015869267
2013	72.20951787092352
2014	75.47621895664722