Year	Percent change (Units)
1980	7.741
1981	-1.580
1982	2.309
1983	5.243
1984	2.529
1985	12.837
1986	20.291
1987	26.344
1988	10.916
1989	7.009
1990	0.450
1991	0.450
1992	0.450
1993	0.450
1994	7.554
1995	7.225
1996	21.060
1997	20.645
1998	22.048
1999	19.356
2000	22.078
2001	14.666
2002	6.256
2003	3.884
2004	0.537
2005	0.456
2006	-3.367
2007	11.099
2008	3.559
2009	-15.887
2010	9.821
2011	8.858
2012	8.601
2013	-6.370
2014	7.348
2015	-2.627
2016	-6.620
2017	3.628
2018	3.437
2019	-4.891
2020	-39.244
2021	-7.186
2022	41.219
2023	10.202
2024	9.720
2025	9.718
2026	6.862
2027	4.647
2028	3.112
2029	3.061