It's bound to be very quiet. Throughout the month of February this year a total of 233 pilgrims who started in SJPP got their Compostelas, so if you calculate that backwards, it's not too many starting each day. Your biggest challenge will be the weather (you'll be crossing the Pyrenees in mid-winter; the Napoleon route is closed as it's too dangerous) and there's a good chance you'll encounter storms and snow throughout your time on the camino, so make sure you have the right gear and heed the advice of locals!
The other challenge will be the accommodation, as lots of albergues are open seasonally. Here's a list to give you an idea:
http://www.aprinca.com/alberguesinvierno/
There are a number of threads on this forum on doing a "winter camino", so you'll find lots of information if you type that into the search box. The main advice is about having the right clothes (in a nutshell, you'll be dealing with a lot of wind, rain and mud, but it can also get warm so wear layers), and about albergues in winter - most albergues have very basic facilities, are poorly insulated and have no heating, so make sure you wrap up tight and don't expect to be able to dry your clothes (for me this was the biggest inconvenience of a winter camino - unless you've used waterproof gear everything stays wet!)