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:
| Episode | Broadcast date | Run time | Viewers (in millions) | Archive |
| --- | --- | --- | --- | --- |
| " Episode 1 " | 27April1968 | 23:47 | 7.2 | Only stills and/or fragments exist |
| " Episode 2 " | 4May1968 | 22:50 | 6.9 | Only stills and/or fragments exist |
| " Episode 3 " | 11May1968 | 24:25 | 7.5 | 16mm t/r |
| " Episode 4 " | 18May1968 | 24:14 | 8.6 | Only stills and/or fragments exist |
| " Episode 5 " | 25May1968 | 21:55 | 6.8 | Only stills and/or fragments exist |
| " Episode 6 " | 1June1968 | 23:10 | 6.5 | 35mm t/r |
Question:
Name the broadcast date of 6.9 million viewers
Answer:
4May1968