abnormality vs nonregularity

abnormality

noun
  • The state or quality of being abnormal; variation; irregularity. 

  • Something abnormal; an aberration; an abnormal occurrence or feature. 

nonregularity

noun
  • The state or condition of being nonregular. 

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