True, but if you account for inflation, Star Wars and LOTR have both managed three (SW has had six straight if you ignore the animated spin-offs). Of course, something that has only been done by SW and LOTR is still incredibly rare. I don't think anyone would have imagined we'd even be having this discussion about The Hunger Games before the first movie came out.
Using last year's average ticket price (BOM's 2014 price is going to go up when they update it for summer when more people go to fancy theatres), the original Indiana Jones trilogy adjusts to over $400M as well.