Historical clue formulations

• Go from 30 to 35 degrees, say — 2015-05-06
• Increase the pitch of — 2015-03-28
• Make more inclined — 2014-10-01
• Increase in verticality — 2006-06-05
• Raise, as prices — 2002-11-03
• Increase, as an incline — 2002-10-18
• Make more precipitous — 1998-05-24
• Increase the slope of — 1998-03-08
• Increase the angle of elevation — 1994-02-09