* Country: Graduation rates and definitions of "failure" differ significantly across countries. Some countries have more rigorous requirements than others.
* Definition of "failure": Does "failure" mean not graduating at all? Failing to graduate within four years? Failing to achieve a certain GPA? The definition greatly impacts the numbers.
* Data Collection Methods: Data collection methods vary, leading to inconsistencies in reporting.
While you can find graduation rates for specific countries or states, compiling a global figure of "high school failures" is impossible due to the lack of standardized definitions and data collection. You'd need to specify a particular country or region to get a more meaningful answer.