Movement between unserved, underserved, and served over the last three Form 477 filings

How quickly has broadband deployment progressed? How fast have Census blocks moved from unserved to underserved (or served)? And is there any movement in the other direction? From served areas to underserved or unserved? For the whole United States, there were 6.76 million unserved housing units in the Dec 2019 Form 477 data. 950,000 of those housing units moved to underserved in the next update for June 2020. 402,000 became served. By the Dec 2020 update, we’re at 3.78 million unserved housing units, which includes a small amount of movement towards unserved, but mostly movement away, as expected.