Transaction per minute

This is for stock market, I want to know for every minutes how many transactions happen. Many transactions can happen into 1 minute.
For evey "time" that appear = 1 transaction. I insert a picture of my spreadsheet.
So I want to know how many transaction/minute. Then later show it in a graph.

Exemple here at 9:30, there was 23 transactions.

For 9:31, there was 6 transactions. So

1 at 09:31:54
1 at 09:31:36
1 at 09:31:33
1 at 09:31:27
1 at 09:31:24
1 at 09:31:24

Time
09:35:09
09:34:51
09:34:51
09:34:48
09:34:48
09:34:48
09:34:48
09:34:42
09:34:30
09:34:27
09:33:57
09:33:48
09:33:42
09:32:21
09:32:21
09:32:15
09:31:54
09:31:36
09:31:33
09:31:27
09:31:24
09:31:24
09:30:57
09:30:36
09:30:36
09:30:33
09:30:33
09:30:33
09:30:33
09:30:30
09:30:30
09:30:30
09:30:30
09:30:30
09:30:27
09:30:21
09:30:18
09:30:15
09:30:03
09:30:03
09:30:03
09:30:03
09:30:00
09:30:00
09:30:00