This output can be divided in 4 parts. The first part covers the workers paying homage to the master. That's our usual output from all programs.
Then we can see the master process sending the first 11 rows to worker processes. The master does not send a job to itself (typical, isn't it?).
The third distinct part is the longest. Here we see the master process receiving answers from worker processes and immediately sending the next row to each process that comes back with the answer.
Finally, when the master will have sent row 99, it begins to terminate processes returning with answers by sending them empty messages with tag value of 100.