Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Polling Firm | Date | Link | PSOE | Others | Lead |
| --- | --- | --- | --- | --- | --- |
| Election results | October 29, 1989 | HTML | 39.6% 175 | 12.6% 19 | 13.8% |
| Exit polls | Exit polls | Exit polls | Exit polls | Exit polls | Exit polls |
| Sigma Dos | October 23 | HTML | – 168 | – 23 | – |
| ICP Research | October 16–19 | HTML | – 174–178 | – 25–26 | – |
| Opina | October 16–18 | HTML | 41.5% 172–178 | 15.0% 18–27 | 16.5% |
| IIF | October 16–17 | HTML | – 173–183 | – 18–23 | – |
| Demoscopia | October 9–15 | HTML | 41.6% 176–182 | – 17–23 | 18.8% |
| Opina | October 7–11 | HTML | 41.0% 172–178 | 12.4% 18–24 | 17.0% |
| PSOE | October 5 | HTML | – 175–185 | – | – |
| El País | October 5 | HTML | – 176 | – | – |
| CIS | October 5 | HTML | 43.0% 178–180 | – | 22.0% |
| Metra Seis | September 19–22 | HTML | – 172–179 | – 26–28 | – |
| European Election (seat extrapolation) | June 15, 1989 | HTML | 39.6% 186 | 21.5% 28 | 18.2% |
| Opina | June 4 | HTML | 36.1% | 17.3% | 13.7% |
| Opina | January 17–18 | HTML | 37.9% | 13.0% | 14.8% |
| 1989 | 1989 | 1989 | 1989 | 1989 | 1989 |
| Opina | November 29–30 | HTML | 34.3% | 13.7% | 7.2% |
| 1988 | 1988 | 1988 | 1988 | 1988 | 1988 |
| European Election (seat extrapolation) | June 10, 1987 | HTML | 39.1% 169 | 16.2% 25 | 14.4% |
| Local Elections | June 10, 1987 | HTML | 37.1% | 20.3% | 16.7% |
| 1987 | 1987 | 1987 | 1987 | 1987 | 1987 |
| Gallup | October 19–December 23 | HTML | 42.0% | – | 18.9% |
| Election Results | June 22, 1986 | HTML | 44.1% 184 | 11.1% 17 | 18.1% |
Question:
Which date has a PSOE of 36.1%?
Answer:
June 4