Strong growth might lift revenue from local online ads past the total for newspapers by the end of next year, according to a survey by Borrell Associates. Local online revenue is projected to increase 21.3% this year, after a similar gain in 2011. The survey also found that Gannett and many smaller newspaper companies saw a substantial gain in online revenue last year, although some bigger companies, including E.W. Scripps, The Washington Post Co. and Media General, posted a modest decline. Still, the average newspaper website took in $2.2 million, ahead of sites for TV and radio stations.