The species progress graph in the graphs analysis section (not the summary screen) shows points to allow precise values to be seen on hover.

Ideally it would be possible to hover anywhere on the line to see a tooltip, and points would refer to individual (or multiple) entries as annotations. Hovering over them would show a details and allow linking to them.

The original design included this behaviour, but it was not included in the most recent update to this graph, as it was considerably more work:
https://twitter.com/Bird_Journal/status/752965475399852032

Feel free to vote if you'd like to see this.