Year	Percent change (Units)
1980	13.899
1981	13.683
1982	-10.607
1983	11.313
1984	26.432
1985	-3.243
1986	-16.745
1987	7.204
1988	22.602
1989	1.367
1990	-12.285
1991	0.298
1992	11.994
1993	7.078
1994	10.409
1995	10.063
1996	2.564
1997	13.315
1998	5.936
1999	7.284
2000	12.920
2001	8.702
2002	8.471
2003	14.237
2004	16.029
2005	10.304
2006	3.758
2007	6.156
2008	-1.738
2009	-8.625
2010	7.173
2011	2.361
2012	1.011
2013	2.877
2014	-0.362
2015	8.887
2016	4.214
2017	4.785
2018	3.417
2019	-1.674
2020	-1.334
2021	2.283
2022	6.133
2023	9.363
2024	3.021
2025	4.071
2026	3.530
2027	2.996
2028	2.641
2029	2.152