| Passive ownership stake (update) | SC 13G/A | 1999-02-12 | - |
| Passive ownership stake | SC 13G | 1999-02-08 | - |
| 10-K405 | - | 1999-02-05 | 1998-12-31 |
| Proxy statement | DEF 14A | 1999-02-05 | 1999-03-23 |
| Major company event | 8-K | 1998-12-21 | 1998-12-21 |
| Quarterly report | 10-Q | 1998-10-30 | 1998-09-30 |
| Quarterly report | 10-Q | 1998-08-10 | 1998-06-30 |
| Major company event | 8-K | 1998-05-28 | 1998-05-28 |
| Quarterly report | 10-Q | 1998-05-12 | 1998-03-31 |
| Major company event | 8-K | 1998-04-23 | 1998-04-23 |
| Major company event | 8-K | 1998-02-24 | 1998-02-23 |
| 424B3 | - | 1998-02-19 | - |
| Passive ownership stake | SC 13G | 1998-02-17 | - |
| Passive ownership stake | SC 13G | 1998-02-17 | - |
| Proxy statement | DEF 14A | 1998-02-10 | 1998-03-24 |
| Major company event | 8-K | 1998-02-10 | 1998-02-09 |
| Passive ownership stake (update) | SC 13G/A | 1998-02-10 | - |
| 424B3 | - | 1998-02-09 | - |
| 10-K405 | - | 1998-02-06 | 1997-12-31 |
| Major company event (amended) | 8-K/A | 1998-02-06 | 1998-01-21 |
| Passive ownership stake (update) | SC 13G/A | 1998-02-06 | - |
| Major company event | 8-K | 1998-02-05 | 1998-01-21 |
| Securities registration | S-3 | 1997-12-05 | - |
| Quarterly report | 10-Q | 1997-10-30 | 1997-09-30 |
| Quarterly report | 10-Q | 1997-07-29 | 1997-06-30 |
| Activist ownership stake (update) | SC 13D/A | 1997-06-27 | - |
| Quarterly report | 10-Q | 1997-05-09 | 1997-03-31 |
| Activist ownership stake (update) | SC 13D/A | 1997-03-10 | - |
| Passive ownership stake (update) | SC 13G/A | 1997-02-14 | - |
| Passive ownership stake (update) | SC 13G/A | 1997-02-14 | - |
| 10-K405 | - | 1997-02-14 | 1996-12-31 |
| 424B3 | - | 1997-02-14 | - |
| Proxy statement | DEF 14A | 1997-02-11 | 1997-03-26 |
| Passive ownership stake (update) | SC 13G/A | 1997-02-11 | - |
| Passive ownership stake (update) | SC 13G/A | 1997-02-07 | - |
| Employee stock plan | S-8 | 1996-12-23 | - |
| Prospectus supplement | 424B2 | 1996-11-27 | - |
| Quarterly report | 10-Q | 1996-11-14 | 1996-09-30 |
| Securities registration | S-3 | 1996-11-01 | - |
| Major company event | 8-K | 1996-10-15 | 1996-07-29 |
| Quarterly report | 10-Q | 1996-08-13 | 1996-06-30 |
| Activist ownership stake (update) | SC 13D/A | 1996-05-17 | - |
| Quarterly report | 10-Q | 1996-05-03 | 1996-03-31 |
| 8-A12B | - | 1996-04-19 | - |
| 10-K405 | - | 1996-02-29 | 1995-12-31 |
| Proxy statement | DEF 14A | 1996-02-20 | 1996-03-26 |
| Passive ownership stake | SC 13G | 1996-02-14 | - |
| PRE 14A | - | 1996-02-09 | 1996-03-26 |
| Activist ownership stake (update) | SC 13D/A | 1995-11-13 | - |
| Quarterly report | 10-Q | 1995-11-08 | 1995-09-30 |
