Year	Percent change (Units)
1980	-61.845
1981	46.724
1982	18.102
1983	-10.893
1984	-67.900
1985	241.505
1986	30.045
1987	-51.642
1988	113.545
1989	-15.136
1990	-14.113
1991	55.235
1992	-15.891
1993	20.322
1994	-36.037
1995	20.315
1996	-31.901
1997	35.428
1998	9.451
1999	-22.914
2000	-2.639
2001	-20.148
2002	11.064
2003	-33.662
2004	-4.602
2005	10.765
2006	12.050
2007	17.163
2008	-36.137
2009	27.184
2010	20.313
2011	-24.302
2012	-28.069
2013	25.844
2014	51.162
2015	-20.688
2016	31.455
2017	-6.854
2018	8.078
2019	-0.002
2020	-31.031
2021	70.031
2022	102.104
2023	-14.527
2024	1.822
2025	4.972
2026	5.753
2027	7.846
2028	6.781
2029	9.786