Year	Percent
1990	29.246
1991	29.139
1992	29.567
1993	29.505
1994	29.417
1995	29.212
1996	29.074
1997	28.773
1998	28.577
1999	29.152
2000	29.223
2001	29.004
2002	28.897
2003	28.614
2004	28.433
2005	28.076
2006	28.088
2007	27.563
2008	27.62
2009	27.489
2010	26.976
2011	26.514
2012	26.161
2013	25.8
2014	25.52
2015	25.255
2016	25.343
2017	25.161
2018	24.98
2019	24.798
2020	24.617
2021	24.435
2022	24.254
2023	24.072
2024	23.891
2025	23.709
2026	23.528
2027	23.346
2028	23.165
2029	22.983
2030	22.802