WORDCOUNT

86,800 English words ranked by usage. Not sure how trustworthy.

Some examples:
majority 1027, minority 2840
felixstowe 24087, crease 24088
spectrum 5037, plectrum 62433
massage 9631, message 1473
mercury 6519, venus 10849, earth 1051, mars 9840
dystopia (no ranking), box 1148, blog (unranked)
employed 2003, hoped 2004, conclusion 2005
mob 9177, mafia 13314, cajun 39555
color 27077, colour 867
yank 36030, yankee 26484, doodle 41928
conquistador 86800