Just often has this late of a snowfall occurred?

Looking back through the climate data, it's been quite some time since we've experienced a snowfall this late in the season. 

This was put together from the Chicago NWS:

THE JANUARY 12TH CALENDAR DAY BROUGHT 4.5 INCHES OF SNOW OFFICIALLY AT ROCKFORD. THIS WAS THE FIRST EVENT WITH AT LEAST TWO INCHES OF SNOWFALL THIS SEASON. LOOKING BACK SINCE 1940..THE AVERAGE FIRST CALENDAR DAY WITH TWO INCHES OF SNOW IN ROCKFORD DURING A WINTER SEASON IS DECEMBER 7TH. IN THOSE PAST 71 YEARS...THERE HAVE ONLY BEEN THREE WINTERS TO SEE A FIRST TWO INCH PLUS SNOW IN A DAY LATER THAN THE 2011-2012 WINTER /RETURN FREQUENCY OF ONCE EVERY 24 YEARS. THIS LATE OF A FIRST TWO INCH SNOWFALL HAD NOT BEEN SEEN SINCE THE 2001-2002 WINTER...WHEN THE FIRST TWO INCH PLUS EVENT MATERIALIZED ON JANUARY 16TH 2002. THE LATEST SINCE 1940 WAS DURING THE 1980-1981 WINTER...WHEN THE FIRST TWO INCH PLUS EVENT DID NOT OCCUR UNTIL FEBRUARY 10 1981.