Stats Canada had the Beltline pop at 16,355 in 2006, so there's been almost 3,500 increase in population over the past 6 years. Also, there's been a pretty big amount of new office space, retail, renovations, and soon enough hotels to go along with the new condos.
I believe in the early 2000's the Beltline population was just over 14K, so there has been some pretty good growth since then. It looks like this decade is going to be a lot bigger in terms of urban growth/densification. Even right now, every inner city neighborhood has multiple projects on the go. I was pretty impressed on my trip this past weekend. Pixel is going to look really good coming into Kensington from downtown!