Hydro Review, Jan. 2014, by Alan Hardcastle & Sally Zeiger Hanson.
http://www.hydroworld.com/articles/hr/print/volume-33/issue-1/article/when-20-of-your-workforce-is-retiring-employment-challenges-for-electric-power.html

"Between now and 2018, about 17% of the current electric power workforce in the Pacific Northwest is expected to retire, and it is becoming more challenging to fill open positions. What are employers to do?"