'scholar':
The Jewish Exile or 'The Exile' of 70 years began in 607 BCE with the destruction of Jerusalem by Nebuchadnezzar in 607 BCE. Such an invasion and deportation of the population caused soon thereafter to flee to neighbouring countries such as Egypt whereas others were deported along with others in the first deportation in 597 BCE to Babylon.
So the 70 years began on the day or week they were deported from Jerusalem?