Dingxian vs Republic of China

Dingxian

name
  • Synonym of Ding County in Hebei, China. 

  • Synonym of Dingzhou, a town in Hebei, China. 

Republic of China

name
  • A state of East Asia; modern-day Taiwan (began in the early 20th century in mainland China). 

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