I have a 2015 13" MacBook Pro, and I'm on 85% after 940 cycles (5560/6559mAh - I guess the battery was smaller back then). I most often run it on the charger, but fairly often run it on battery down to a low percentagr too.

Just another datapoint here for a 2019 16" MBP bought at launch: 8542/8587 mAh for ~99.5%.

I have 46 cycle count, I keep it at my desk plugged in at 100% the vast majority of the time.

I don't think that's how you calculate it. You measure the Full Charge Capacity against what it's originally rated at. (What I've seen online is that the original capacity is 8790)

In your case, that'd be 8587/8790, or 97.7%.

To elaborate, you can install Coconut Battery and it will show the percentage I'm describing under "Design Capacity"