optimum vs world-beating

optimum

adj

  • The best or most advantageous; surpassing all others. 

noun

  • The best or most favorable condition, or the greatest amount or degree possible under specific sets of comparable circumstances. 

world-beating

adj

  • Superior to all others of its sort. 

How often have the words optimum and world-beating occurred in a corpus of books? (source: Google Ngram Viewer )