from pillar to post vs to and fro

from pillar to post

adv

  • From one place (or person, or task) to another; from post to pillar, hither and thither. 

to and fro

adv

  • Back and forth; with a reciprocating motion. 

verb

  • To go back and forth; to alternate. 

How often have the words from pillar to post and to and fro occurred in a corpus of books? (source: Google Ngram Viewer )