The article doesn't cite any methodology, so I don't know what to make of it. It does state:

"The mood swings between depression and mania that characterize bipolar disorder typically occur along a continuum, with a high frequency of days with mood swings that are not necessarily extreme enough to count as an episode of major depression, mania, or hypomania."

Since episodes exist along a continuum, & the article doesn't state exactly how to identify mood swings severe enough to qualify in their study, I'd say we don't have enough info from the bphope article (thus wrote the smart arse ). I'm sure the actual study guesses more accurately than I'm giving it credit for.

I'm BP I & I WISH the ratio was 3:1...if I could manage to stay out of trouble, that is. As I've grown older, I've noticed that depression is the dominant symptom that kicks me in the nether regions. Depression sucks...That's the result of my real life study.

Thanks for posting this, BirdDancer. It's food for thought.