|
| year | production | consumption |
| 1984 | .68 | .81 |
| 1985 | .65 | .73 |
| 1986 | .63 | .73 |
| 1987 | .69 | .72 |
| 1988 | .48 | .63 |
| 1989 | .61 | .63 |
| 1990 | .52 | .63 |
| 1991 | .46 | .54 |
| 1992 | .54 | .50 |
| 1993 | .24 | .41 |
| 1994 | .48 | .36 |
| 1995 | .35 | .28 |
| 1996 | .31 | .31 |
| 1997 | .66 | .58 |
| 1998 | .68 | .65 |
| 1999 | .02 | .43 |
| 2000 | .04 | .20 |
| 2001 | .04 | .16 |
| 2002 | .09 | .12 |
| 2003 | .02 | .10 |
| 2004 | .02 | .08 |
| 2005 | .04 | .05 |
| 2006 | | .03 |
| 2007 | .04 | .03 |
| 2008 | .02 | .03 |
| 2009 | .02 | .03 |
| 2010 | .04 | |
|
|