Chart looks a bit different if you go beyond 1935. Seems a bit dishonest to not show a larger picture, but what do I know?
Here is a chart for the entire 20th century:
The reality: Communists destroyed the Russian economy and derailed the very successful industrialization under Nicholas II. There was literally no reason for a 15-year gap of terror and mass murder, and then having to play catch-up with even more terror and mass murder