Year	% of total
1990	61.606028003433565
1991	61.04418999358033
1992	59.641214058386886
1993	58.71447843524927
1994	59.40643863075392
1995	58.488511943119015
1996	59.877136229819705
1997	58.37774111029986
1998	55.33570699069832
1999	54.807204265090476
2000	53.48773905385219
2001	52.84940388747682
2002	55.78966406984983
2003	58.40999575256705
2004	60.1278995947571
2005	61.76687379932156
2006	63.294833688992526
2007	60.34453576904294
2008	67.36311788602704
2009	62.98099988779099
2010	66.53352189878957
2011	67.90461915473541
2012	67.53043718909277
2013	65.13116233243699
2014	64.45783725104623
2015	64.30586867938749
2016	62.28440582251318