Today, February 24th 2016, marks the end of Drupal 6.

Drupal 6 lasted for over 8 years and was the backbone behind many of the projects that made Drupal famous.

The image below shows the first 3 years of Drupal 6. You can see that Drupal 6 peaked at the beginning of 2011, just before the release of Drupal 7. At its height, there were just over 300,000 Drupal 6 sites.