I found in the times that I was looking, that usually it comes in batches. I would have nobody for a certain amount of time, and then tons! Keep in mind too, that the time of year will factor in. I was also advertising in December, but got little to no response. Many people don't want to change providers right before the holidays, so they will wait until Jan or Feb, when things settle down.
Some areas take longer than others too, as there are differences with demographics (usually easier to fill up in newer neighborhoods, where there are young families often, etc).

Good luck!!!!