Year	Percent change (Units)
1980	10.752
1981	4.121
1982	9.953
1983	8.152
1984	5.400
1985	-19.186
1986	-6.999
1987	11.202
1988	26.946
1989	33.704
1990	24.400
1991	24.549
1992	3.089
1993	11.781
1994	29.883
1995	27.707
1996	1.461
1997	4.188
1998	-17.761
1999	10.453
2000	23.698
2001	-8.146
2002	6.565
2003	2.246
2004	22.955
2005	4.668
2006	15.874
2007	1.673
2008	-8.698
2009	-23.454
2010	18.121
2011	4.597
2012	0.257
2013	5.864
2014	4.130
2015	1.273
2016	0.521
2017	12.833
2018	3.118
2019	-3.160
2020	-2.837
2021	18.648
2022	19.157
2023	-5.469
2024	4.180
2025	4.067
2026	4.061
2027	3.874
2028	3.843
2029	3.781