* Data Collection Challenges: Tracking graduation numbers globally is incredibly difficult. Different countries have varying education systems, data collection methods, and reporting standards. Many countries lack reliable data altogether.
* Definition of "Graduate": The definition of "graduate" itself varies. Does it include only university graduates? What about vocational schools, trade schools, or postgraduate degrees?
* Time Lags: Data is often collected and reported with a significant delay.
While organizations like UNESCO collect education statistics, they provide aggregate figures rather than precise global graduate counts. To get an accurate number would require a massive, coordinated international effort with consistent data collection standards—something that doesn't currently exist.