Professor Uerpmann said the estimates of time using genetic data were "very rough".

BBC: Humans 'left Africa much earlier'

These estimates are made by economists and data analysts at Zillow using an algorithm with real-world data from contractors, such as finish levels and material rates.

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Using data from over 2, 000 interviews with businesses in the food production industry, the report estimates that food producers draw on a pool of between 420, 000 and 611, 000 temporary workers.

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