US Army UH-60 – serials/identify

It’s not my field…

Anyone here who can help with the serials of the US Army helicopters? It seems more complicated than the normal USAF-system.

For example: The following two UH-60 visited Munich Airport (EDDM/MUC) last week, the serials were: 0-26071 and 0-24642.
Which year means “0-” ?