|
| year | production | consumption |
| 1980 | | 5.51 |
| 1981 | | 9.92 |
| 1982 | | 3.31 |
| 1983 | | 6.61 |
| 1984 | | 9.92 |
| 1985 | | 20.94 |
| 1986 | | 12.13 |
| 1987 | | 19.84 |
| 1988 | | 23.15 |
| 1989 | | 22.05 |
| 1990 | | 37.48 |
| 1991 | | .06 |
| 1992 | | 35.49 |
| 1993 | | 12.79 |
| 1994 | | 10.91 |
| 1995 | | 4.74 |
| 1996 | | 1.02 |
| 1997 | | .82 |
| 1998 | | 1.18 |
| 1999 | | .07 |
| 2000 | | .14 |
| 2001 | | .61 |
| 2002 | | 11.58 |
| 2003 | | 14.63 |
| 2004 | | 13.74 |
| 2005 | | 4.41 |
| 2006 | | 7.72 |
| 2007 | | 13.23 |
| 2008 | | 7.72 |
| 2009 | | 6.61 |
| 2010 | | 13.23 |
| 2011 | | 12.13 |
|
|
