Year	Percent
1990	29.166
1991	29.137
1992	29.344
1993	29.404
1994	29.453
1995	29.454
1996	29.662
1997	30.121
1998	30.062
1999	30.037
2000	29.999
2001	30.228
2002	30.222
2003	30.201
2004	30.345
2005	30.384
2006	30.32
2007	30.302
2008	30.315
2009	30.229
2010	30.062
2011	30.03
2012	29.98
2013	29.84
2014	29.734
2015	29.57
2016	29.434
2017	29.418
2018	29.403
2019	29.387
2020	29.371
2021	29.356
2022	29.34
2023	29.324
2024	29.308
2025	29.293
2026	29.277
2027	29.261
2028	29.246
2029	29.23
2030	29.214