Year	Percent
1997	8.55964
1998	7.48249
1999	7.89573
2000	8.01439
2001	7.38976
2002	6.46092
2003	6.85388
2004	7.21663
2005	7.13813
2006	7.0897
2007	7.37486
2008	8.84564
2009	9.60957
2010	10.64057
2011	13.95588
2012	17.91774
2013	15.94766
2014	12.0988
2015	12.5204
2016	12.87989
2017	16.02234
2018	16.32382
2019	18.28225
2020	19.99512
2021	25.07638
2022	20.62812