Year	% of total
1991	45.89758942372022
1992	36.40715805538135
1993	36.72043961037028
1994	35.74668692520351
1995	35.947883211627534
1996	35.703230957297784
1997	36.19729609284547
1998	36.608224421290416
1999	36.01803757285948
2000	35.061947408447296
2001	35.62278171241863
2002	35.34446765424493
2003	34.484058966045325
2004	34.44836763656359
2005	34.18886560771494
2006	33.65322906873661
2007	32.82014254708164
2008	33.28245815531382
2009	34.42243663451197
2010	32.64536352787393
2011	32.41101682114965
2012	31.72199825664322
2013	31.66341029586132
2014	33.090441725574514
2015	31.373610681400642
2016	32.278205964708725