Year	Units
1964-01-01	1079.2991765229800
1965-01-01	1611.0677525593699
1967-01-01	1673.2442176716700
1968-01-01	1839.1449727143001
1969-01-01	1865.5118615411300
1970-01-01	2342.7307584895098
1971-01-01	2713.6831034994602
1972-01-01	2874.7172426980200
1973-01-01	3228.1642978808000
1974-01-01	2457.2778209686003
1975-01-01	4305.6475729694200
1976-01-01	5192.7517416803200
1977-01-01	7969.6282150953200
1978-01-01	9259.2814137739300
1979-01-01	6977.6375795361100
1980-01-01	3039.1652765931800
1981-01-01	3986.1941926377700
1982-01-01	6677.2148462364900
1983-01-01	5463.8295078007600
1984-01-01	6242.7059510241300
1985-01-01	7948.9269387436810
1986-01-01	6986.2086343062600
1987-01-01	5388.1427360168700
1988-01-01	5523.4637109049700
1989-01-01	7431.6855741821200
1990-01-01	9623.3333333333300
1991-01-01	13978.0833333333010
1992-01-01	16591.1666666667000
1993-01-01	12315.7500000000000
1994-01-01	9128.6666666666600
1995-01-01	10418.5833333333010
1996-01-01	11651.7500000000000
1997-01-01	13322.2500000000000
1998-01-01	15012.0833333333000
1999-01-01	21809.2500000000000
2000-01-01	24185.1666666667000
2001-01-01	23351.1666666667000
2002-01-01	22374.0833333333000
2003-01-01	21441.0833333333000
2004-01-01	24140.9166666667000
2005-01-01	22477.3333333333000
2006-01-01	22305.7500000000000
2007-01-01	23312.0833333333030
2008-01-01	22274.5833333333000
2009-01-01	18310.8333333333000
2010-01-01	11791.7500000000000
2011-01-01	8140.0000000000010
2012-01-01	4873.2500000000000
2013-01-01	4891.3333333333300
2014-01-01	5935.1666666666700
2015-01-01	6317.0000000000000
2016-01-01	6572.7500000000000
2017-01-01	7342.9166666666700