When workers suddenly lose three hours of work

Then we get a recession!

From Mankiw, it's the number of hours working to buy a barrel of crude.  Note in  20023 to 2008, workers lost the equivalent of five hours of work.  Our economy uses about 60 barrels per person per day, says IndexMundi.  The numbers do not match because Mankiw uses labor rates, which is not a complete incomer set.  But, it is clear the 2009 crash was an oil shortage.