Pony Express vs Post

Pony Express

name
  • A 19th-century mail service delivering messages across North America by means of riders on horseback. 

Post

name
  • A common name (often in combination) for a newspaper or periodical, such as The Washington Post or the New York Post. 

  • A city, the county seat of Garza County, Texas. 

  • A village in Iran 

  • A surname. 

  • An unincorporated community in Oregon 

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