I'm not quite sure. Within my work team, Word is only used occasionally, specifically for anything document related. Excel, on the other hand, is used all the time from typical number crunching to keeping track of tasks (despite how much I despise using it for the latter). I also imagine that small businesses, like restaurants, don't require Word very often, but a lot of them use Excel for finances, inventory, etc.

In regards to PowerPoint, I imagine it lags pretty far behind in usage compared to both Excel and Word. Not many people are making presentations in the grand scheme of things. My intuition says that it's mostly upper management and maybe a single person in a group using PowerPoint "often".