Comic book based movies are the three biggest films of 2014 worldwide so far, according to Box Office Mojo, with almost $1.9 billion worth of tickets sold by those three films alone.  In order, the top three worldwide grosses of 2014 to date are:
 

• $709.3 million -- Captain America: The Winter Soldier
• $690.0 million -- The Amazing Spider-Man 2
• $500.2 million -- X-Men: Days of Future Past

A fourth comic-based movie (although the comic has yet to be released), 300: Rise of an Empire, is lodged at #8, giving the segment four of the top ten movies, with over $2.23 billion sold. 
 
And with Guardians of the Galaxy and Sin City: A Dame to Kill For still coming up, comic movies could top $3 billion for the year.