There's no conspiracy. The measures haven't changed markedly in 70 years.
Still, there are dipshits out there asserting that Bill Clinton or Ronald Reagan or Zombie Thomas Jefferson waved his hand at some point and created a magical lower unemployment calculation.
Idiocy. Conservatives want live babies so they can raise them to be dead soldiers. - George Carlin
It may be some transatlantic transpolant.
Besides which, everyone knows that 78.2% of govt statistics are hooey keep to the Fen Causeway