Year	Percent change (Units)
1980	0.068
1981	18.124
1982	38.792
1983	9.072
1984	21.275
1985	21.923
1986	5.324
1987	-18.227
1988	-0.166
1989	43.538
1990	21.670
1991	-0.360
1992	-11.865
1993	-17.213
1994	40.980
1995	7.227
1996	-11.688
1997	18.050
1998	16.448
1999	-8.231
2000	6.390
2001	5.902
2002	19.741
2003	6.807
2004	4.988
2005	-20.754
2006	29.336
2007	-6.166
2008	23.947
2009	-41.854
2010	2.165
2011	53.139
2012	-8.032
2013	6.949
2014	-6.046
2015	-3.380
2016	13.354
2017	27.836
2018	-9.364
2019	7.803
2020	-14.245
2021	-20.752
2022	20.736
2023	18.007
2024	0.174
2025	4.588
2026	4.018
2027	3.607
2028	2.409
2029	2.859