|
| year | production | consumption |
| 1980 | | .40 |
| 1981 | | .40 |
| 1982 | | .50 |
| 1983 | | .50 |
| 1984 | | .50 |
| 1985 | | .57 |
| 1986 | | .57 |
| 1987 | | .55 |
| 1988 | | .55 |
| 1989 | | .79 |
| 1990 | | .81 |
| 1991 | .10 | .86 |
| 1992 | 1.55 | .81 |
| 1993 | 4.50 | .88 |
| 1994 | | .88 |
| 1995 | | .87 |
| 1996 | 17.09 | .89 |
| 1997 | 52.42 | .96 |
| 1998 | 83.00 | .96 |
| 1999 | 102.00 | .96 |
| 2000 | 167.50 | 1.53 |
| 2001 | 181.44 | 1.15 |
| 2002 | 212.56 | 1.15 |
| 2003 | 206.47 | 1.19 |
| 2004 | 365.46 | 1.03 |
| 2005 | 362.53 | 1.07 |
| 2006 | 342.87 | 1.11 |
| 2007 | 345.37 | 1.73 |
| 2008 | 336.83 | 5.20 |
| 2009 | 321.98 | 3.12 |
| 2010 | 297.78 | 5.37 |
| 2011 | 276.87 | |
|
|