BOM (or was it The-Numbers?) used to have more Star Wars data, which showed the movie slowing to a dribble at $219 million. So ~220M seems right. The data is now missing, I know not why.
According to http://www.in70mm.com/news/2003/star_wars/ (I can't get inserting links to work), The first release lasted all the way until the second, but the second one lasted just 16 weeks, leading to a total of 265.1 million. So the "first release" can be either 220M or 265.1M, but it can't be 307M - Star Wars was not in theatres continuously for over 4 years straight.