The 911 calls were over the course of a year from what I read, although who knows with the way this case is being handled and manipulated. If Zimmerman was tailing Martin in the vehicle, he had to exit at some point to confront him (degree or method, showing sidearm or not, no one knows). Zimmerman claimed he was returning to his vehicle when attacked and it is his word versus a dead kid’s, so who knows. Irregardless, he had no proof this kid committed a crime and followed and approached him anyway, all of this could have been avoided by simply doing what both the 911 operator and Neighborhood Watch suggest which is report only. He went looking for trouble.
“In the past 11 years, George Zimmerman has made 46 calls reporting suspicious black people that he spotted in his neighborhood. “
http://trayvonmartinmurdercase.blogspot.com/2012/03/read-george-zimmerman-911-call-report.html