Statistics that are being viewed in an open worksheet are temporary datasets that disappear when the worksheet is closed. You can view these temporary datasets, as well as statistics that are archived to disk, as a list on one page.
On the BUI, you can also view since when the analytics dataset was created and when the data was last accessed. The last access time of an analytics dataset is updated when a dataset is created, read, saved, resumed, or used to plot graph in the BUI.