Year	Percent
1991	4.915
1992	8.884
1993	8.026
1994	7.608
1995	5.443
1996	3.874
1997	4.112
1998	4.142
1999	4.251
2000	6.005
2001	6.308
2002	6.413
2003	5.578
2004	4.777
2005	4.618
2006	4.628
2007	4.754
2008	4.502
2009	5.249
2010	5.068
2011	3.972
2012	3.889
2013	3.957
2014	4.085
2015	4.352
2016	4.308
2017	4.414
2018	4.422
2019	4.429
2020	4.426
2021	4.425
2022	4.425