sea sponge vs sponger

sea sponge

noun
  • sponge (animal, Porifera) 

sponger

noun
  • One who uses a sponge. 

  • A device for sponging cloth by means of a perforated adjustable cylinder. 

  • A parasitic hanger-on. 

  • A person or vessel employed in gathering sponges from the sea. 

How often have the words sea sponge and sponger occurred in a corpus of books? (source: Google Ngram Viewer )