My guess is that it’s because there are so many math-related majors at UCLA - Math, Applied Math, Financial Actuarial Math, Math & Econ, and so on.
Remember that these are solely transfer applicants. I haven’t met many Statistics majors in general, honestly. I’m sure it’s popular at UCLA, but there are also many related fields to choose from (perhaps many people are interested less in Stats than they are in other things that UCLA offers).
Just a wild guess. 2013 had a similarly low number of applicants for Stats.
I’m sure the program is stellar, if that’s what you’re worried about.
I’m still deciding whether or not to apply under Math/Econ or Stat as well. I see that the Stat has the higher acceptance rate, and I definitely wanna major in it, but part of me wants to try econ as well. I’ve been contemplating the math/econ major and a stat minor if I get in, but getting in is the tricky part lol.