Minorities comprised more than 70 percent of the estimated 110,800  dropouts in California’s six largest metropolitan areas in 2008. Had only half of the 78,850 African America, Latino, Asian American and American Indian dropouts  graduated from high school instead, they would be earning an average of nearly $1.3 billion in income per year and be giving their local economy a jolt.

That’s the chief finding of  a study by the Alliance for Excellent Education, a Washington, D.C.-based advocacy group that examined the impact of dropping out of high school in the nation’s 45 largest metropolitan areas, including six in California.  Using an econometric model tailored to each  area, the study assumed that between 48 and 56 percent of the high school graduates would go on to get a certificate or degree at  a community college or four-year college.

Here’s the breakdown for California’s six largest metropolitan areas:

• Fresno: If 2,800 high school dropouts had earned a diploma, they would earn a collective $27.5 million in an average year, spending an average of $20.2 million. Tax revenue from their income and spending would grow by around $3.4 million in an average year. The Alliance estimated 51% of these graduates would pursue higher education.

• Los Angeles-Long Beach: If 36,540 dropouts had earned a diploma, they  would earn $272.5 million in an average year. Tax revenues would grow an average $46.1 million. The Alliance estimated 48% of these graduates would pursue higher education.

• Sacramento: If 3,350 dropouts had earned a diploma, they earn a collective $23.8 million in an average year. Tax revenue would grow $2.9 million. The Alliance estimated 56% of these graduates would pursue higher education.

• San Diego: If 5,800 dropouts had earned a diploma, they would earn a collective $50.4 million in an average year. Tax revenue  would grow  $5.9 million. The Alliance estimated 54% of these graduates would pursue higher education.

• San Francisco-Oakland: if 5,800 dropouts had earned a diploma, they would earn a collective $86.9 million in an average year. Tax revenues would grow $8 million. The Alliance estimated 56% of these graduates would  pursue higher education.

• San Jose: If 2,000 dropouts had earned a diploma, they would earn a collective $25.2 million in an average year. Tax revenues would grow $2.8 million. The Alliance estimated 54% of these graduates would pursue higher education.

Reporting by Educated Guess intern Annie Shuey.