Year	Percent
1991	4.11
1992	4.064
1993	4.008
1994	4.068
1995	4.129
1996	4.164
1997	4.206
1998	4.194
1999	4.154
2000	4.129
2001	4.095
2002	4.115
2003	4.131
2004	4.127
2005	4.174
2006	4.171
2007	4.158
2008	4.206
2009	4.243
2010	4.254
2011	4.287
2012	4.479
2013	4.562
2014	4.552
2015	4.493
2016	4.524
2017	4.549
2018	4.61
2019	4.675
2020	4.747
2021	4.816
2022	4.884