Various probes have gone faster - with the cruising speeds depending whether they headed towards the sun or away. After New Horizons got a gravity boost from Jupiter, it sailed out to pluto at 23k/s and arrived going 15k/s. https://blogs.scientificamerican.com/life-unbounded/the-fast...

I'll have to look and see what they have planned for the Mars missions. I'm sure we've jumped ahead a bit in practical engineering terms, but just haven't had a mission to show it yet.

You could use it like economists use the consumer price index - all relative to year. So you could have the Apollo, or human space year, or something and reference HSY_{1969}, or HSY_{ion thruster}, etc.