| Form type | Document | Filing | Description | Filing date | Reporting date | File number(s) |
|---|---|---|---|---|---|---|
| 4 | Open Document | Open Filing | Jun 10, 2022 | Jun 9, 2022 | 000-31127 | |
| 4 | Open Document | Open Filing | Mar 3, 2022 | Mar 1, 2022 | 000-31127 | |
| 4 | Open Document | Open Filing | Mar 3, 2021 | Mar 2, 2021 | 000-31127 | |
| 4 | Open Document | Open Filing | Jun 3, 2020 | Jun 1, 2020 | 000-31127 | |
| 3 | Open Document | Open Filing | PRIMARY DOCUMENT | Jun 27, 2019 | Jun 25, 2019 | 811-23403 |
| 4 | Open Document | Open Filing | Mar 25, 2019 | Mar 22, 2019 | 000-31127 | |
| 4 | Open Document | Open Filing | Mar 11, 2019 | Mar 8, 2019 | 000-31127 | |
| 4 | Open Document | Open Filing | Mar 5, 2019 | Mar 1, 2019 | 000-31127 | |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Mar 5, 2018 | Mar 1, 2018 | 000-31127 |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Mar 8, 2017 | Mar 7, 2017 | 000-31127 |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Mar 3, 2017 | Mar 1, 2017 | 000-31127 |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Mar 8, 2016 | Mar 4, 2016 | 000-31127 |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Mar 3, 2016 | Mar 2, 2016 | 000-31127 |
| 4 | Open Document | Open Filing | PRIMARY DOCUMENT | Mar 12, 2015 | Mar 11, 2015 | 000-21888 |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Feb 27, 2015 | Feb 25, 2015 | 000-31127 |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Sep 4, 2014 | Sep 3, 2014 | 000-31127 |
| 4/A | Open Document | Open Filing | OWNERSHIP DOCUMENT | Aug 27, 2014 | Aug 25, 2014 | 000-31127 |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Aug 26, 2014 | Aug 25, 2014 | 000-31127 |
| 4 | Open Document | Open Filing | PRIMARY DOCUMENT | Mar 19, 2014 | Mar 18, 2014 | 000-21888 |
| 4 | Open Document | Open Filing | OWNERSHIP DOCUMENT | Mar 3, 2014 | Feb 27, 2014 | 000-31127 |
| 4 | Open Document | Open Filing | PRIMARY DOCUMENT | Jan 6, 2014 | Dec 31, 2013 | 000-21888 |