amass vs assemble

amass

verb
  • To accumulate; to assemble. 

  • to gather a great quantity of; to accumulate. 

  • To collect into a mass or heap. 

assemble

verb
  • To put together. 

  • To translate from assembly language to machine code. 

  • To gather as a group. 

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