Year	% of total
1990	34.68654497576048
1991	39.46194024327754
1992	41.407236406557054
1993	44.46622168584489
1994	45.47708522421385
1995	47.705497035337316
1996	50.8167421623596
1997	52.18288819557426
1998	54.77198765972975
1999	53.72583480720714
2000	51.74026605061432
2001	50.89161935161565
2002	44.12866106144668
2003	54.10964070257262
2004	52.585121315357675
2005	48.747744995801476
2006	49.88519815661141
2007	59.796516207294324
2008	58.23419450748284
2009	61.01384844628886
2010	58.46591556030318
2011	62.54867536441694
2012	59.064116282112025
2013	68.62871976684167
2014	66.45438503938342
2015	67.51417111435802
2016	65.37660973249734