This seems to have some data that suggests they have seen a decline: https://onlinelibrary.wiley.com/doi/full/10.1002/ijc.35081

There's a chart about 2/3 down the page that shows a drop in several age groups, and a particularly striking drop in the 20-29 age group: https://onlinelibrary.wiley.com/cms/asset/fd3e820c-4610-4c4e...