I notice you’re not going after OP for his vague title with picture, but I’m fair game.
To make it abundantly clear (which you can infer from the other chart posted in the thread), the population change was mostly non-Latvians entering before the USSR splintered and leaving afterwards. I made a reference to habits in that region of wiping out locals and replacing them with ethnic “russians” to rebut the vague sarcastic “the decline was after the USSR splintered so communism=good” title.
Was that clear enough?
And I was noting that the USSR had a tendency to shift their ethnic populations around to wipe out (still don’t understand how you took that term to mean anything other than killing local populations, it’s “wipe out” as in “erase”) other local ethnic populations. We saw the numbers increase until the USSR splintered and then fall off because there was no longer a system to support that shifting of ethnic populations. This crowd should know about it unless they only believe in or talk about the beneficial parts of communism and ignore the ugly parts that regularly get implemented.