Year	Percent change (Units)
1980	-21.720
1981	60.183
1982	66.915
1983	-7.413
1984	8.079
1985	43.743
1986	-2.563
1987	-6.250
1988	13.806
1989	17.294
1990	26.489
1991	22.100
1992	38.200
1993	64.600
1994	12.700
1995	3.700
1996	0.361
1997	-3.780
1998	4.174
1999	4.472
2000	12.636
2001	-13.731
2002	-4.571
2003	-9.289
2004	5.978
2005	11.734
2006	14.416
2007	7.560
2008	13.660
2009	4.884
2010	16.731
2011	21.667
2012	6.685
2013	10.552
2014	22.155
2015	-4.798
2016	13.000
2017	7.637
2018	12.450
2019	8.068
2020	-3.648
2021	9.000
2022	2.560
2023	7.065
2024	5.233
2025	1.635
2026	2.814
2027	3.174
2028	5.349
2029	5.479