Year	Percent
1990	12.442
1991	12.404
1992	13.626
1993	14.985
1994	14.974
1995	15.157
1996	13.975
1997	14.72
1998	15.308
1999	14.432
2000	14.233
2001	12.806
2002	14.121
2003	13.753
2004	14.251
2005	14.777
2006	15.073
2007	14.322
2008	14.789
2009	14.883
2010	14.672
2011	14.252
2012	14.959
2013	14.75
2014	14.177
2015	15.174
2016	15.067
2017	15.086
2018	15.106
2019	15.125
2020	15.144
2021	15.163
2022	15.182
2023	15.201
2024	15.22
2025	15.239
2026	15.258
2027	15.277
2028	15.297
2029	15.316
2030	15.335