Year	Total
1985	12115000000
1986	12935000000
1987	13951000000
1988	13560000000
1989	13737000000
1990	13808000000
1991	14482000000
1992	13122000000
1993	14808000000
1994	15866000000
1995	16880000000
1996	17280000000
1997	17953000000
1998	18582000000
1999	19050000000
2000	19923000000
2001	20786000000
2002	21982000000
2003	22923000000
2004	24267000000
2005	25510000000
2006	27370000000
2007	29943000000
2008	32463000000
2009	32945000000
2010	35908000000
2011	38806000000
2012	41036000000
2013	43330000000
2014	45550000000
2015	48270000000
2016	51467000000