Year	Percent change (Units)
1980	16.228
1981	3.030
1982	10.280
1983	38.073
1984	25.801
1985	35.424
1986	-15.231
1987	-4.881
1988	10.325
1989	0.602
1990	8.101
1991	11.617
1992	-2.379
1993	-0.605
1994	-4.906
1995	20.417
1996	-10.431
1997	12.505
1998	6.381
1999	5.169
2000	-0.642
2001	25.870
2002	-5.145
2003	16.896
2004	38.054
2005	7.342
2006	15.013
2007	3.237
2008	24.444
2009	-11.993
2010	16.345
2011	8.314
2012	7.544
2013	1.993
2014	12.567
2015	49.858
2016	13.337
2017	-14.181
2018	-12.072
2019	11.609
2020	10.980
2021	10.802
2022	-14.283
2023	24.347
2024	1.497
2025	4.088
2026	5.077
2027	4.603
2028	4.531
2029	3.070