Year	Percent
1991	1.267
1992	1.244
1993	1.171
1994	1.15
1995	1.13
1996	1.235
1997	1.184
1998	1.158
1999	1.076
2000	1.106
2001	1.309
2002	1.442
2003	1.62
2004	1.839
2005	1.923
2006	2.074
2007	2.239
2008	2.407
2009	2.545
2010	2.744
2011	2.595
2012	2.572
2013	2.545
2014	2.596
2015	2.51
2016	2.467
2017	2.487
2018	2.484
2019	2.464
2020	2.448
2021	2.432
2022	2.413