The Nasdaq Composite Index (INDEXNASDAQ:IXIC) today broke the 4,000 mark for the first time since September 2000. Sounds high but it's still well below its peak of 5,048 during the dot-com bubble of the late '90s.

It took the index more than 10 years to double from its starting point of 100 points, and just half that time -- a little over five years -- to double again.

The index hit a post-bubble low of 1,114 in October 2003. It doubled from that point to 2,241 in November 2005. It’s been eight years since that date, and it would take 400 more points for the index to be at double its last milestone.

Here’s a timeline of every time the Nasdaq Composite Index doubled in value since its inception in 1971, and from its low after the dot-com bubble crashed:

A timeline of Nasdaq Composite Index milestones IBTimes/Lisa Mahapatra