* Age: Younger individuals without a diploma are likely to have lower incomes than older individuals who may have accumulated work experience, even without a high school diploma.
* Occupation: Some jobs requiring less formal education can still offer decent pay (skilled trades, for example), while others pay significantly less.
* Geographic location: Income levels vary greatly by region and state. Cost of living also plays a role.
* Full-time vs. Part-time Employment: Consistent full-time employment will naturally lead to higher annual income.
While precise figures are hard to pinpoint without specifying these factors, studies consistently show that individuals without a high school diploma earn considerably less than those with a high school diploma or higher education. You'll find data on median income by educational attainment from sources like the U.S. Census Bureau (in the United States) or equivalent statistical agencies in other countries. These sources will give you a much more accurate picture, though remember to consider the caveats mentioned above when interpreting the numbers.