Issue number
Datafiles
| Valid Observations | 5010 |
| Valid Observations | 8966 |
| Valid Observations | 10039 |
| Valid Observations | 6748 |
| Valid Observations | 9427 |
| Valid Observations | 13681 |
| Valid Observations | 19825 |
| Valid Observations | 14421 |
| Valid Observations | 6194 |
| Valid Observations | 7221 |
| Valid Observations | 11426 |
| Valid Observations | 4565 |
| Valid Observations | 6164 |
| Valid Observations | 11092 |
| Valid Observations | 6464 |
| Valid Observations | 3290 |
| Valid Observations | 12774 |
| Valid Observations | 1502 |
| Valid Observations | 1998 |
| Valid Observations | 3173 |
| Valid Observations | 1838 |
| Valid Observations | 1968 |
| Valid Observations | 3600 |
