For the UK they're declining from a peak in the late 90s, but they were kinda flat before that, and in in any case you're talking about a difference of under 1% either way. There was never a time that the UK's murder rate was anything like 56/100k, at least not in the last century (before the late 19th century, useful stats aren't really available, but some estimates do show _very_ high murder rates in the 19th century).
Murders have been declining, right? I wonder how much of this is due to comparing historical murders with current murder rates?