Here's something also interesting... extrapolating that same price trend back into history, since 12 Feb 2013 (more than 4 years now), we have never been more than 20% below the trendline.  Applying a 20% contingency to the above numbers would mean the following potential lower bounds:


   Date       Target    80% Lower Bound
 1 Jun 2017   $1,243      $   994
 1 Jul 2017   $1,335      $ 1,068
 1 Aug 2017   $1,436      $ 1,149
 1 Sep 2017   $1,546      $ 1,236

1 Oct 2017   $1,660      $ 1,328

 1 Nov 2017   $1,786      $ 1,429
 1 Dec 2017   $1,918      $ 1,534

 1 Jan 2018   $2,064      $ 1,651
23 Mar 2018   $2,500      $ 2,000
 8 Jun 2018   $3,000      $ 2,400
 8 Oct 2018   $4,006      $ 3,205

 1 Jan 2019   $4,899      $ 3,919

 1 Jan 2020   $11,630     $ 9,304

 1 Jan 2021   $27,675     $22,140