Year	Percent change (Units)
1981	16.700
1982	38.256
1983	60.058
1984	59.518
1985	61.340
1986	-13.514
1987	3.125
1988	-0.337
1989	-8.196
1990	6.985
1991	-0.069
1992	2.820
1993	-2.742
1994	43.746
1995	11.698
1996	-0.003
1997	3.727
1998	6.587
1999	1.124
2000	6.616
2001	12.181
2002	6.200
2003	5.863
2004	5.095
2005	3.163
2006	3.807
2007	3.737
2008	5.470
2009	4.997
2010	5.429
2011	4.919
2012	2.564
2013	4.866
2014	2.575
2015	1.603
2016	2.000
2017	-0.225
2018	2.590
2019	4.304
2020	-0.638
2021	2.875
2022	5.020
2023	2.132
2024	5.688
2025	0.399
2026	2.152
2027	2.278
2028	1.799
2029	1.334