Currently two items are available in preferences: 1) toggle to save upload/download totals across Deluge sessions (default on, otherwise you would start from zero each session), 2) a button to reset your totals.
Nothing fancy. Just remember: sharing is caring!

Egg Releases: https://github.com/holocronweaver/deluge-ratio/releases
Source and README: https://github.com/holocronweaver/deluge-ratio/
Tested on Linux and Windows using Deluge 1.3.15, but should work on MacOS as well.
Does not currently work with web UI, but if anyone wants to add such functionality I'll happily accept a PR. Currently using the stock GTK plus symbol for the status bar icon, but looking for a better icon to replace it.
p.s. - I realize there are plugins that do parts of this already, but I couldn't find one that worked exactly the way I wanted: optionally track total down/up across sessions and show the ratio and totals in the status bar. I'm surprised this seemingly isn't built into Deluge. It's an important feature of modern torrent clients as it encourages sharing ALL your downloads by gamifying with an overall score. Maybe in 2.0?