phase down vs tamp

phase down

verb
  • To gradually reduce the size or scale of 

tamp

verb
  • To reduce the intensity of. 

  • To drive in or pack down by frequent gentle strokes 

  • To plug up with clay, earth, dry sand, sod, or other material, as a hole bored in a rock. 

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