Year	Percent change (Units)
1980	5.145
1981	16.419
1982	-28.784
1983	-34.211
1984	-14.975
1985	-23.865
1986	26.144
1987	-9.376
1988	24.986
1989	-2.030
1990	24.396
1991	30.270
1992	0.895
1993	-1.968
1994	0.264
1995	3.904
1996	-0.703
1997	1.449
1998	1.213
1999	-10.499
2000	5.794
2001	-1.247
2002	-9.416
2003	21.800
2004	9.814
2005	6.149
2006	-0.135
2007	2.156
2008	4.339
2009	-9.818
2010	7.291
2011	10.038
2012	5.395
2013	1.604
2014	1.953
2015	2.701
2016	4.262
2017	-0.747
2018	8.324
2019	-6.425
2020	-5.194
2021	5.234
2022	9.227
2023	-6.825
2024	-0.820
2025	12.051
2026	7.017
2027	3.487
2028	3.994
2029	4.224