| 1990 | 1991 | 1992 | 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TW Plc 1990 | TW Plc 1991 | TW Plc 1992 | TW Plc 1993 | TW Plc 1994 | TW Plc 1995 | TW Plc 1996 | TW Plc 1997 | TW Plc 1998 | TW Plc 1999 | TW Plc 2000 | TW Plc 2001 | TW Plc Dec 2001 | TW Plc Dec 2002 | RWE TW Plc Dec 2003 | RWE TW Plc Dec 2004 | RWE TW Plc Dec 2005 |