There are a ton of ways to measure Internet traffic. By many of those gauges, it appears that demand for bandwidth is rapidly increasing. But a couple of countervailing forces are keeping it from growing as fast as it otherwise might, as the networking company Sandvine's biannual study of broadband traffic illuminates.

If you look at the results one way, you get a surprising picture. BTIG Research put together the past three years' worth of per capita fixed (not mobile) data usage and found that the growth rate seems to be leveling off:

That would be big news! For a couple of reasons, though, it's not quite what it seems.

First of all, it doesn't really matter how much data someone consumes on a monthly basis. Comcast and Verizon aren't charging by total volume over home Internet connections (yet). What really matters is how much data people are using during peak periods, since that's what determines the size of the connection a provider will have to build. Think of the Internet as a highway: It doesn't cost anything to let a few cars drive on it, but it will be expensive to widen the road to avoid traffic jams during rush hour.

By that metric, Sandvine says, data usage is still rocketing upward by some 40 percent per year -- more and more people are streaming shows during the peak hours between 7 and 10 p.m., rather than watching them on a television (which is why pay-TV subscriptions continue to drop).

So why the difference in growth between overall monthly data usage and peak-hour data usage? In part, it has to do with how we're getting our content. File-sharing through sites such as BitTorrent has plummeted in North America. It now accounts for less than 10 percent of total traffic during peak hours -- 10 years ago, it was 60 percent. So instead of downloading something whenever during the day to watch later, people have options like Netflix or Hulu, which they can just cue up after work. Streaming video tends to take up less bandwidth, since people only download as much as they watch rather than downloading the whole thing only to stop in the middle. And right now, "real-time entertainment" accounts for most of our evening Internet usage, with Netflix taking the lion's share.

Another complicating factor: the rapid rise of mobile. Although mobile broadband traffic is still a tiny percentage of fixed-access traffic, your smartphone or tablet also uses bandwidth much more efficiently. So as more people people watch more videos on their mobile devices rather than on computers -- and mobile is increasingly a sole broadband option -- they're theoretically freeing up a lot of bandwidth that they might have otherwise used.

Overall, the numbers seem to show that we're going to need more broadband capacity, and the industry says it's racing to keep up. But as viewership modes change, the demand is a lot less than it otherwise might've been.

The headline has been amended to reflect that BitTorrent does, in fact, still exist.