Year	% of total
1990	15.006755452615325
1991	16.246321984026903
1992	33.80719680142159
1993	68.19698173153296
1994	62.10675150229763
1995	34.50818198165798
1996	25.297714837463793
1997	23.055233040305193
1998	24.82636084638992
1999	20.99002973587546
2000	21.164820409533398
2001	16.849434290687554
2002	30.041674216343537
2003	36.02981276131613
2004	33.134328358208954
2005	28.067120468576856
2006	30.718734219828313
2007	31.41742963716514
2008	31.143847487001736
2009	35.602186563216364
2010	39.37759975350485
2011	33.49932705248991
2012	28.89497262319562
2013	28.184176394293125
2014	25.703225806451613
2015	28.285677650980894