we exported $37.1B worth of vacuum tubes last year. I could be wrong but that amount seems wildly implausible. Could the category actually be "Vacuum tubes, etc." where "etc" is semiconductors?
The only things I really know of that would still use vacuum tubes are esoteric high-end audiophile amplifiers, and some "old school" guitar amps (Marshall, Hiwatt, etc). Is there really that big a market? Are they used for anything else?
You are overlooking things like magnetrons, x-ray tubes, photomultipliers, CRTs (which still have a lot of applications outside of the video display sphere), krytons and so forth. It's not all about diodes, triodes, tetrodes and pentodes.