Year	Percent
1991	4.484
1992	4.969
1993	5.663
1994	8.204
1995	7.889
1996	8.166
1997	6.653
1998	7.042
1999	8.637
2000	9.733
2001	10.331
2002	10.157
2003	10.532
2004	10.398
2005	8.648
2006	8.256
2007	7.446
2008	6.501
2009	6.038
2010	5.407
2011	4.85
2012	4.483
2013	4.238
2014	3.662
2015	3.366
2016	3.556
2017	3.665
2018	3.624
2019	3.554
2020	3.444
2021	3.341
2022	3.242