(Olympia, WA)  --  Washington's state unemployment rate is the lowest it's been since August 2007.  The Employment Security Department says the jobless rate for March was four-point-seven percent, compared to four-point-nine percent the previous month.  Washington employers added ten-thousand-700 nonfarm jobs in March.  The state's labor force rose to three-point-68-million people, up 15-hundred from February.