related_tweet: @danielgriswold over past 15 yrs, us biggest export by far was ust's, on avg ~$667b/yr.  next biggest was machinery at ~$200b/yr.  given that, one would expect the sectors of the us econ that "mfr &amp; export ust's" to become the richest in the us - 7 of 10 richest us counties surround washington.