Year	% of total
1994	9.5
1997	7.7
2000	12.1
2001	12
2003	13.9
2004	13.2
2006	20.1
2007	18
2009	24.4
2010	26.5
2011	31.7
2013	36.5
2014	42.1
2016	49.8
2017	67.8
2018	52.7
2019	59