API is down?
https://www.1szb.com/json/topQuotations.html?symbol=2Graphed volume data is incorrect. It appears to be worse the longer the time-span that you view. When you are viewing a 1-year span, the volume segments of 'Week starting monday....' are far too low. When you zoom in, more volume appears. Have you been aware of this issue? Doesn't seem like it would be too difficult to fix.
Remember that the data is showing "last 24h volume" at the time recorded, not volume for the timespan itself as most graphs show. Edit: I just doubled checked and it does seem like there is an issue here, looking into it. Thanks.
A reasonably complete analysis of the coinmarketcap pages stored on archive.org suggests that it's closer to 30%.
Interesting! I'm sure there are some coins that were added and removed between snapshots too.