Year	% of total
1990	57.04936115009559
1991	60.958741225445536
1992	63.95023857605149
1993	58.70566842357475
1994	55.01212324242055
1995	59.617372713109916
1996	56.48112493321214
1997	51.962435845328955
1998	60.20736394325431
1999	64.13677909547953
2000	62.96871118490734
2001	66.86494270843738
2002	69.76361952296392
2003	72.66289643587258
2004	74.58817390713453
2005	66.29703557257156
2006	61.41925682262027
2007	50.02167603689647
2008	58.752408582010425
2009	58.43193423800321
2010	66.15445935179388
2011	70.30288978588206
2012	67.19820251823424
2013	67.77685634817314
2014	70.29075683644093
2015	67.08473319182586
2016	70.35320567914926