horizontal vs in straight line

horizontal

adj
  • Relating to horizontal markets 

  • Involving wines of the same vintages but from different wineries. 

  • Having the two notes sound successively. 

  • Relating to sexual intercourse. 

  • Perpendicular to the vertical; parallel to the plane of the horizon; level, flat. 

noun
  • A horizontal component of a structure. 

  • Horizon. 

  • A Tasmanian shrub or small tree whose main trunk tends to lean over and grow horizontally, Anodopetalum biglandulosum 

in straight line

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