Why do younger men like older women these days?

Something that pops up in mind...because that's my observation when mingling with people in my circle and when chatting with people online. Seems like it's a trend these days? Not that it's new, yet it's quite interesting to see such a shift of preference where the age gaps between the younger guy and the older lady can be more than 5 years, 10 years (yet to see 20 years in my circle). Perhaps I belong to a more traditional type, preferring older guys at least 3 years older if possible.