hydro pole vs utility pole

hydro pole

noun
  • A utility pole. 

utility pole

noun
  • A tall cylinder, often made from the trunk of a tree, usually topped by a cross beam, used by a public utility to carry wire, cable or conduit through the air, for the transportation of electricity, cable television, telephone or similar services. 

How often have the words hydro pole and utility pole occurred in a corpus of books? (source: Google Ngram Viewer )