send in vs submit

send in

verb
  • to cause (something) to be delivered, especially by post/mail 

  • to give (one's name), present (one's card) when making a social call 

  • to send (a batsman) on to the field to bat. 

submit

verb
  • To enter or put forward for approval, consideration, marking etc. 

  • To yield (something) to another, as when defeated. 

  • To win a fight against (an opponent) by submission. 

  • To yield or give way to another. 

  • To subject; to put through a process. 

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