early on vs undeveloped

early on

adj

  • Early in a process. 

adv

  • At an early stage. 

undeveloped

adj

  • not developed or used 

  • not built on, unbuilt; not ready for building on 

  • lagging behind others, especially in economic or social matters 

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