From the available polling data (which tends to cut it off at 44 rather than 40), Sanders won roughly 51.2% of the under 44 vote.

That's nothing to scoff at, but "half" is a far cry from "almost everyone." https://twitter.com/MenshevikM/status/1248648158349058049

"The Democratic Party is trending leftwards"

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"Sanders is the future of the Party"