If you are looking at the timeline from 1st to 5th edition, then it is a timespan of about 132 years.
1st edition was set in 1357 DR, while 5th edition (The Sundering) is placed at 1484 DR, and the Adventurers League play starts in 1489 DR.
This places it in line with the Phandelver, since Hotenow erupted in 1451 DR.
Numbers taken from http://forgottenrealms.wikia.com/wiki/Forgotten_Realms which purports to take the dates from the various box sets and info releases from TSR/WotC.