Well, courtesy of
Worldwide Box Office, here's one possible indication:
RANK WORLD B.O. (in millions)
0007 $ 925.5 Star Wars: Episode I - The Phantom Menace (1999)
0016 $ 848.5 Star Wars: Episode III - Revenge of the Sith (2005)
0019 $ 798.0 Star Wars (1977)
0032 $ 649.7 Star Wars: Episode II - Attack of the Clones (2002)
0042 $ 572.9 Star Wars: Episode VI - Return of the Jedi (1983)
0047 $ 538.2 Star Wars: Episode V - The Empire Strikes Back (1980)
0512 $ 146.0 Star Trek: First Contact (1996)
0537 $ 139.0 Star Trek: The Motion Picture (1979)
0559 $ 133.0 Star Trek IV: The Voyage Home (1986)
0612 $ 120.0 Star Trek: Generations (1994)
0653 $ 112.5 Star Trek: Insurrection (1998)
0751 $ 97.0 Star Trek: The Wrath of Khan (1982)
0752 $ 96.9 Star Trek VI: The Undiscovered Country (1991)
0825 $ 87.1 Star Trek III: The Search for Spock (1984)
1102 $ 63.0 Star Trek V: The Final Frontier (1989)
1125 $ 61.1 Star Trek: Nemesis (2002)
This of course doesn't take into account that Trek is primarily a product of TV, which is why I qualified with "one possible indication"
