Year	Percent change
1980	3.05
1981	5.589
1982	3.206
1983	4.61
1984	4.177
1985	3.744
1986	3.985
1987	2.931
1988	2.388
1989	4.298
1990	4.603
1991	4.203
1992	4.801
1993	4.324
1994	4.513
1995	4.77
1996	5.013
1997	5.304
1998	5.044
1999	5.421
2000	5.6
2001	4.834
2002	4.845
2003	5.776
2004	6.108
2005	6.302
2006	6.851
2007	6.518
2008	5.515
2009	5.315
2010	6.03
2011	6.494
2012	6.26
2013	6.038
2014	6.314
2015	6.842
2016	7.202
2017	7.584
2018	7.727
2019	7.289
2020	7
2021	7
2022	7
2023	7
2024	7