load (up) vs top up

load (up)

top up

verb
  • to refill the drink of (somebody) 

  • to extend the credit of something 

  • to refill (or recharge) something 

  • to add to a number or amount, to bring something up to a certain level 

  • To have sex (with). 

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