There is this small paragraph in the DMG on page 133.
"You can hand out as much or as little treasure as you want. Over the course of a typical campaign, a party finds treasure hoards amounting to seven rolls on the Challenge 0- 4 table, eighteen rolls on the Challenge 5- 10 table, twelve rolls on the Challenge 11- 16 table, and eight rolls on the Challenge 17+ table."
The tables referenced are the Treasure Hoard Tables. Earlier in the section it also mentions that each roll doesn't have to be a separate haul. If a monster is known as a treasure collector like dragons, it's hoard can contain multiple rolls on the appropriate table.