|
| year | production | consumption |
| 1980 | .59 | .59 |
| 1981 | .31 | .31 |
| 1982 | .31 | .31 |
| 1983 | .27 | .27 |
| 1984 | .12 | .12 |
| 1985 | .24 | .24 |
| 1986 | .20 | .20 |
| 1987 | .78 | .78 |
| 1988 | .71 | .71 |
| 1989 | 1.10 | 1.10 |
| 1990 | 1.14 | 1.14 |
| 1991 | 1.18 | 1.18 |
| 1992 | 1.22 | 1.22 |
| 1993 | 1.25 | 1.25 |
| 1994 | 1.22 | 1.22 |
| 1995 | 1.45 | 1.45 |
| 1996 | 1.52 | 1.52 |
| 1997 | 26.49 | 26.49 |
| 1998 | 14.13 | 14.13 |
| 1999 | 17.66 | 17.66 |
| 2000 | 21.19 | 21.19 |
| 2001 | 10.59 | 10.59 |
| 2002 | 12.36 | 12.36 |
| 2003 | 13.07 | 13.07 |
| 2004 | 13.07 | 13.07 |
| 2005 | 14.13 | 14.13 |
| 2006 | 14.13 | 14.13 |
| 2007 | 21.19 | 21.19 |
| 2008 | 40.97 | 40.97 |
| 2009 | 40.97 | 40.97 |
| 2010 | 37.79 | 37.79 |
| 2011 | 36.37 | 36.37 |
|
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