Year	Percent
1997	6.09788
1998	23.39269
1999	15.32212
2000	12.67441
2001	8.02625
2002	11.48628
2003	12.84676
2004	12.70118
2005	8.06371
2006	10.67881
2007	5.9622
2008	16.72636
2009	20.95903
2010	17.50177
2011	26.76105
2012	22.85203
2013	21.00905
2014	22.23695
2015	29.55805
2016	37.63239