Definify.com

Webster 1828 Edition

adv.

In a small degree; to a small amount; very little.

inconsiderably ‎(comparative more inconsiderably, superlative most inconsiderably)

To an inconsiderable degree.
- 2009 February 25, Roy Blount Jr., “The Kindle Swindle?”, in New York Times:
  Income from audio books helps not inconsiderably to keep authors, and publishers, afloat.