The last thirty days
Every exchange this site tracks, recorded once a day, so a single price can be checked against where it has actually been.
History is still building
This page fills in once the daily cron job has run a few times. Set it up from the README if you have not already, and check back tomorrow.
Why a daily figure and not every tick
The homepage board moves minute to minute, which is right for a decision you are making right now. This page exists for a different question: whether today's price is normal, or a real outlier compared with recent weeks. One clean recorded price per exchange per day answers that more clearly than a chart of every fluctuation would.