Not if “faster” refers to computation rate rather than runtime, in which case it becomes 100/81 i.e. 23% faster.
Even in other contexts it can be ambiguous.
Yesterday I drove 60mph, today I drove 50% faster.
Yesterday I got there in 1 hour, today I got there 50% faster.
It's not really possible to tell them apart without looking at the numbers.
If you've rewritten something to better use cachelines, removed saturating memory bandwidth, etc then sure you've increased The computation rate. But that's rarely how these language specific optimizations occur.