Up until the 12 and 12 came out in 1955 (I think) the standard time for taking all twelve steps was four weeks. When the 12 and 12 came out, it was anticipated that the period would stretch out to 12 weeks. That is about three steps a month. Lightning fast by today's standards, but considered a backward step by many at the time.
It took me a little over the twelve weeks, a snails pace compared to Sugarbear, who went through them for the first time in her first two weeks if I recall correctly.