shiftable vs transportable

shiftable

adj
  • That can be shifted 

transportable

adj
  • Capable of being transported; easily moved. 

noun
  • A semi-permanent building, such as a portable classroom in a school, or accommodation for fly-in, fly-out workers. 

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