A ‘standard’ 44 gallon (55 US gallon) drum can hold a tad over 218 litres.
There are reasons for them being ‘filled’ to 190 litres in some places, 200 in others and 205 in yet others.
Don’t sweat it. Those who do should subscribe to BBC 4’s ‘Boring Talks’
https://podcasts.apple.com/au/podcas...s/id1332490817