sexually transmitted disease vs tabes dorsalis

sexually transmitted disease

noun
  • Any of various diseases that are usually contracted through sexual contact. 

tabes dorsalis

noun
  • neurosyphilis in the form of such degeneration. 

  • tabes of the back; a degeneration of the sensory neurons of the spinal cord carrying afferent information. 

How often have the words sexually transmitted disease and tabes dorsalis occurred in a corpus of books? (source: Google Ngram Viewer )