user: Question: When was the percentage of trains arriving within 5 minutes of scheduled time 89.6%?
Columns: ['Period', '% trains arriving within 5 mins of scheduled time (over three months)', 'Change over same quarter the previous year', '% trains arriving within 5 mins of scheduled time Moving Annual Average (MAA)', 'Change over previous year as a whole']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Apr - Jun 2007', '91.4%', 'Up 0.8%', '89.0%', 'Up 0.2%']
SQL:

assistant: SELECT "Period" FROM "Table" WHERE "% trains arriving within 5 mins of scheduled time Moving Annual Average (MAA)" = '89.6%';