"Often" is a term that means different things to different people, so it's not an informative descriptor in and of itself. In a dialogue involving two people who have very similar frames of reference or can be acceptable, but, in general, it's bad form. I frequently use it on this forum, esp. when informally and quickly summarizing findings from a large number of studies without having done any statistical analyses or even tabulating the findings, or even I don't have the exact figures or the sources close at hand. Obviously, whenever there is any doubt as to the meaning of the descriptor in any given conversation, it's appropriate to ask for more specific numbers.
Journalists tend to write for audiences with whom they have much in common, and they may also be afraid of alienating readers by using numbers.

