|
| year | production | consumption |
| 1980 | | 89.00 |
| 1981 | | 85.00 |
| 1982 | | 88.00 |
| 1983 | | 89.00 |
| 1984 | | 85.00 |
| 1985 | | 90.00 |
| 1986 | .48 | 93.84 |
| 1987 | .40 | 92.04 |
| 1988 | .42 | 99.03 |
| 1989 | .30 | 111.33 |
| 1990 | .31 | 116.57 |
| 1991 | .30 | 117.39 |
| 1992 | .23 | 130.13 |
| 1993 | .21 | 134.76 |
| 1994 | .20 | 147.54 |
| 1995 | .30 | 141.63 |
| 1996 | .30 | 137.45 |
| 1997 | .08 | 146.12 |
| 1998 | .10 | 144.20 |
| 1999 | .22 | 157.96 |
| 2000 | .30 | 158.48 |
| 2001 | .40 | 161.22 |
| 2002 | .26 | 164.28 |
| 2003 | .20 | 167.07 |
| 2004 | .20 | 170.29 |
| 2005 | .50 | 174.14 |
| 2006 | .50 | 180.79 |
| 2007 | .50 | 183.18 |
| 2008 | .50 | 215.69 |
| 2009 | .50 | 235.26 |
| 2010 | .50 | 243.92 |
| 2011 | .50 | 198.00 |
|
|