Year	% of total
1992	36.47783733249838
1993	36.15586330184607
1994	34.586380764240296
1995	34.50888548579111
1996	37.04910806249627
1997	38.31313333305569
1998	36.814123076166
1999	36.65371603386801
2000	38.296990296948316
2001	38.24743384906314
2002	36.727909352334954
2003	33.87006319050719
2004	31.77032966864832
2005	32.68681652242697
2006	31.30329667482051
2007	30.838743222865126
2008	31.996029683067334
2009	32.722684595008516
2010	39.27630975666874
2011	39.971870831888815
2012	38.86277813902673
2013	40.671864842047334
2014	42.13264522538714
2015	41.186792810279265
2016	41.75557183363287