Here’s a listing of the top 100 most used fonts from the Fonts.com Web Fonts service for March 2014:

Neue Helvetica
Trade Gothic
Avenir Next
Univers
Avenir
Proxima Nova
Frutiger
Gill Sans
Futura
Helvetica
Museo Sans
Linotype Univers
Museo Slab
DIN Next
Century Gothic
Chaparral
Klint
ITC Avant Garde Gothic
Eurostile LT
Arial
Rockwell
Myriad
Univers Next
ITC Lubalin Graph
ITC Legacy Serif
ITC Caslon No. 224
Neo Sans
ITC Century
VAG Rounded
Motoya Birch
Gill Sans Infant
Optima
Soho Gothic
ITC Legacy Square Serif
Linotype Sketch
Neue Frutiger
Amasis
ITC Franklin Gothic
Swiss 721
Trade Gothic Next
Azbuka
Frutiger Next
PMN Caecilia
ITC Charter
Neue Helvetica eText
Swift
ITC Officina Serif
Bodoni LT
Bookman Old Style
ITC Officina Sans
Bembo
ITC Conduit
Lexia
Calibri
Humanist 777
Linotype Didot
Rotis II Sans
Auriol
Helvetica World
ITC Eras
Rotis Sans Serif
Adobe Garamond
Trade Gothic Next Soft Rounded
Brandon Grotesque
ITC American Typewriter Hellenic
Soho
ITC American Typewriter
C Hei 2 PRC
M Elle PRC
ITC Stone Informal
C Hei PRC
M Lady PRC
M Stiff Hei PRC
Delima
Glypha
Novecento
Droid Sans Mono
Aachen
Monotype News Gothic
Francker
Adobe Caslon
Egyptienne F
Orator
ITC Fenice
Clarendon Text
Baskerville Classico
Caslon Classico
Monotype Goudy
Droid Serif
Perpetua
Slate
Twentieth Century
Comic Strip
Clarendon
Bodoni
Oron
Neue Helvetica Arabic
Droid Sans
Plantin
Rotis Semi Sans