Year	Percent change (Units)
1980	53.960
1981	-12.183
1982	-0.317
1983	6.136
1984	-6.552
1985	21.448
1986	-10.728
1987	22.244
1988	-1.907
1989	-0.108
1990	4.795
1991	-13.359
1992	1.257
1993	5.226
1994	60.350
1995	27.338
1996	2.412
1997	11.986
1998	23.512
1999	-15.213
2000	-9.281
2001	5.839
2002	4.981
2003	3.099
2004	7.321
2005	7.418
2006	7.233
2007	12.167
2008	38.529
2009	-0.824
2010	-5.280
2011	2.927
2012	7.739
2013	-3.172
2014	11.698
2015	15.069
2016	-3.608
2017	8.054
2018	17.870
2019	17.799
2020	-2.998
2021	-6.787
2022	-0.133
2023	24.359
2024	7.872
2025	7.424
2026	12.251
2027	-15.466
2028	14.211
2029	8.500