it definitely contributed but you have no way of knowing that that was the most important factor because you can't go back in time and see what would have happened if all of the other PRs came out without that one.
IF you look at the chart the first green week that inititiated the run followed the 2/13/14 PR announcing the share retirement. That was also the first substantial PR in almost ONE YEAR. It signaled the true revitalization of the company, a belief that had worn off a lot of people after no contact.