How is "Voter Turnout" Calculated?

Factual Questions
1

This is not related to any election in particular. We often hear that voter apathy is rampant in the U.S. because less than half of registered voters vote in even the national elections. Typically the media trumpets this “fact” as a shame to the democratic ideals that we try to project to the rest of the world.

However, I have lived in three different states in five years. I have registered to vote in all of them and sometimes even within multiple precincts within a state.

1)Was I counted as a “no show” everwhere except my current voting precinct even though I did vote?

  1. How are voters that move or pass away deregistered from a particular precinct?

  2. Would these factors cause the often trumpeted statistics to be artificially low given are increasingly mobile society?

2

It got no answers to this valid GQ thread so this is self-serving charity bump for another try.