Graph bunching over time

[mathcolo]

Is your feature request related to a problem? Please describe. It would be nice to be able to know how bunching is changing over time. At the moment we only have a single statistic in single-day view:

Describe the solution you'd like I can see a reduction in variance on the current Route 1 multi-day trips page, but another chart showing the bunching metric specifically would be extra handy.

Additional context