ambulate vs roam

ambulate

verb
  • To walk; to relocate oneself under the power of one's own legs. 

roam

verb
  • To range or wander over. 

  • To use a network or service from different locations or devices. 

  • To transmit (resources) between different locations or devices, to allow comparable usage from any of them. 

  • To wander or travel freely and with no specific destination. 

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