Average income or wages for janitors are available. The rates are considerably below those of software developers and other technical IT staff. There are exceptions to averages, but it's absolutely fair to say that the typical janitor is making far less than the typical software developer.
http://www.bls.gov/ooh/Building-and-Grounds-Cleaning/Janitor...
2012 median pay: $22,320 per year / $10.73 per hour