clock on vs show up

clock on

verb
  • To begin work at the start of the day or start of one's shift. 

  • To record one's time of arrival at work, traditionally by inserting one's card into a timestamping machine. 

show up

verb
  • To appear, arrive, or attend, especially suddenly or erratically. 

  • To make visible or expose faults and deficiencies in, usually by outdoing, outperforming, or outcompeting another. 

  • To make visible; to expose. 

  • To be easily visible; to be conspicuous. 

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