With No EXIT Passport Control Does the USA have anyway of knowing when US citizen Left the Country?

Unlike many other Countries...The USA does not Have EXIT Immigration/passport Control...so would they have anyway of knowing if you've been gone for a day or a year?especially if the country you traveled to did not stamp your passport?like when you travel to Mexico...How does the USA know when their Citizens leave?or do they even keep Track of this?With No EXIT Passport Control Does the USA have anyway of knowing when US citizen Left the Country?
The methods that are used to track people are not made public, but I've read that if you fly, or buy a ticket, anywhere in the world it will get sucked-up into the feds data base. Also, if you use a foreign ATM or charge something on a credit card outside the USA it will get into the data base.





I suppose it's possible to get out of the country without the departure being noted, but you'd have to go by land and find a way to live without leaving any electronic footprints of any kind.With No EXIT Passport Control Does the USA have anyway of knowing when US citizen Left the Country?
They do have Passport controls, they are bar coded, if you leave the U.S. to go to China or Ireland etc etc, they are scanned into a computer at that country's immigration, and they know. If you go to Canada or Mexico most likely not unless you use it as a form of ID to cross the border, then it is scanned and they know!
from the minute your ticket is purchased you are logged