find_by_zipcode missing 37212 Nashville, TN

[kquet]

Steps to reproduce

irb(main):001:0> ActiveSupport::TimeZone.find_by_zipcode('37212')
=> nil

Expected behavior

irb(main):001:0> ActiveSupport::TimeZone.find_by_zipcode('37212')
=> "Central Time (US & Canada)"

Actual behavior

irb(main):001:0> ActiveSupport::TimeZone.find_by_zipcode('37212')
=> nil

System configuration

Rails version: Rails 5.0.0.1

Ruby version: ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin16]