In 2011 there were 134 earthquakes in the same area, a sixfold increase over 20th century levels.
en.wikipedia.org The town had a population of 2,750 at the 2010 census, which swells nearly sixfold during the summer.
en.wikipedia.org Between 1661 and 1675 there was a sixfold increase in population from 10,000 to 60,000.
en.wikipedia.org This might be double, treble, fourfold, fivefold, sixfold, tenfold, twelvefold, or even thirtyfold, according to the enormity of the offence.
en.wikipedia.org By 1906, production had multiplied sixfold, and a second production plant had been constructed.
en.wikipedia.org