The Victorian era of course was the most notorious. It’s enough to read novels by Charles Dickens and a myriad of others of this era to see what really went on. And if you get the chance to read the underground writings of this era about CP or canings it will leave even the most hardened CP/caning fan blushing!
Of course, this lasted more than a decade. So it depends on how far back you are willing to go.
Even today in some(if not most)Third World countries mass canings still go on in many schools as a daily fact of life. So it also depends on which region you are referring.
I’ve written in another posting on this site about the judicial mass caning of boys in South Africa. This went on up to the 80s, so it’s fairly recent.
Even if you are referring to the UK the more backward you go the more common and harsher it is.
So there is no such thing as the best decade unless you go back to the Middle Ages and even further.