National trend in home Bath "tubs"

Where could you get sales data to show what people are buying - regular bathtubs, whirlpool bathtubs or air tubs?
Is that published in some industry publication? I have read healt concerns about the jetted tubs and a realtor told me many builders are going back the "soakers" tubs which is fufu talk for a regular bathtub - I think. which way is the industry going? is there a whirlpool trade association?

I doubt you'll find a "national survey" on this topic. Trends like this vary by region and demographics. But I do have a suggestion. My dad annoyed the crap out of me when I was younger by asking several different SME's (subject matter experts) the same question, comparing the answers and then making up his own mind. Try asking your local plumbing supply shops, Home Depot or Lowe's salesmen or home builders what they're selling the most of. That should give you a reasonably good idea. (BTW our builder told us recently people are installing nice walk-in showers over tubs now.)