Year	Percent
1990	3.856
1991	3.896
1992	3.941
1993	3.996
1994	4.061
1995	4.143
1996	4.154
1997	4.142
1998	4.116
1999	4.08
2000	4.039
2001	4.018
2002	3.992
2003	3.964
2004	3.933
2005	3.897
2006	3.923
2007	3.939
2008	3.953
2009	3.982
2010	4.033
2011	4.105
2012	4.186
2013	4.265
2014	4.329
2015	4.37
2016	4.438
2017	4.452
2018	4.467
2019	4.482
2020	4.497
2021	4.511
2022	4.526
2023	4.541
2024	4.556
2025	4.57
2026	4.585
2027	4.6
2028	4.615
2029	4.629
2030	4.644