Statistics
Sheet1
| Years | Demand | Price | Income |
| 1990 | 776 | 214 | 108.4 |
| 1991 | 788 | 214.2 | 108 |
| 1992 | 812 | 208.4 | 107.6 |
| 1993 | 822 | 212.8 | 109.8 |
| 1994 | 864 | 207.6 | 114 |
| 1995 | 882 | 203.4 | 117.8 |
| 1996 | 930 | 194.8 | 122.6 |
| 1997 | 1000 | 199 | 127.2 |
| 1998 | 1072 | 196.8 | 134 |
| 1999 | 1162 | 191.8 | 140.4 |
| 2000 | 1176 | 186.6 | 145.2 |
| 2001 | 1164 | 192.8 | 148.2 |
| 2002 | 1166 | 196.6 | 152.4 |
| 2003 | 1182 | 203.2 | 156.6 |
| 2004 | 1192 | 202.6 | 158.8 |
| 2005 | 1212 | 199.4 | 162.6 |
| 2006 | 1228 | 202.8 | 166.6 |
| 2007 | 1236 | 205.4 | 173.2 |
| 2008 | 1226 | 204.2 | 173.8 |
| 2009 | 1236 | 207.8 | 179.6 |
| 2010 | 1248 | 207.4 | 190.6 |