Year	Percent
1990	29.95
1991	29.943
1992	29.943
1993	29.977
1994	29.945
1995	30.01
1996	30.063
1997	30.041
1998	30.079
1999	30.165
2000	30.199
2001	30.185
2002	30.173
2003	30.165
2004	30.162
2005	30.164
2006	30.199
2007	30.23
2008	30.265
2009	30.308
2010	30.363
2011	30.433
2012	30.513
2013	30.653
2014	30.783
2015	30.889
2016	30.959
2017	31.006
2018	31.052
2019	31.097
2020	31.141
2021	31.18
2022	31.218
2023	31.254
2024	31.289
2025	31.322
2026	31.349
2027	31.375
2028	31.4
2029	31.426
2030	31.454