Administrators at Santa Rosa Junior College briefly had a mystery on their hands this semester.

The number of white students at the college unexpectedly fell more than 11 percent from 17,200 in fall 2010 to 15,230 this fall. Meanwhile, the percentage of Latinos at the school increased by 10 percent.

Officials were stumped by the contrasting numbers until they realized they were consequences of the decision last spring to gut the school's older adult program, which draws an overwhelmingly white audience. Three thousand fewer seniors essentially meant nearly that many fewer white students.

It's an explanation that experts say provides a picture of demographic trends shaping the college — and the state.

Across California, an older, mostly white generation is giving way to a more racially diverse emerging one, said David McCuan, associate professor of political science at Sonoma State University. And SRJC, as the recent numbers suggest, is following suit.

"The community is changing," said Ricardo Navarrette, SRJC's vice president of student services. "As our overall population changes in Sonoma County, it's our mission to change with that population."

Obviously, the climbing Latino enrollment at SRJC is rooted in Sonoma County's changing makeup as the Latino population grows in numbers and the white one decreases.

In 2000, census figures show Latinos made up 17 percent of the county population. By 2010, that number had increased to 25 percent, a 47 percent increase.

The Latino proportion of SRJC enrollment has risen even faster, going from 12.7 percent in fall 2001 to 20.2 percent now, a 59 percent increase.

Students in counselor Geoff Navarro's Puente class Monday morning said there were more reasons behind the increased Latino enrollment than just population growth.

Puente, which means "bridge" in Spanish, is a program geared toward preparing Latino students for four-year colleges. The main Santa Rosa campus has been offering the program for decades. Six years ago, it was added in Petaluma.

Of nearly 30 students in Navarro's class, just four said their parents had attended college. The others said Latinos their age were more frequently choosing higher education for a mix of reasons that include increasing ambitions, more opportunity, the dismal job market and growing appreciation for the importance of education.

"We realize how important education is in our lives," said Tony Padilla, 20, from Petaluma.

While Puente students have their eyes on transferring to some of the state's best schools, SRJC's Latino population also includes many students who arrive with limited language skills.

At least 2,000 of the college's nearly 5,500 Latino students are enrolled in English as a Second Language classes, a number that expected to keep climbing even as funds become scarcer, said Ronald Balsamo, chairman of SRJC's ESL department.

With the state budget woes, the school is paring its ESL offering. In spring 2012, there will be 35 percent fewer for-credit ESL classes than in spring 2009, Balsamo said.

"You have this wave of ESL students coming," he said. "My concern is what are you doing to prepare for this."

More help may be available in the coming years from the federal government. The rising Latino population has put SRJC within striking distance of qualifying as an "Hispanic Serving Institution," allowing it to apply for a share of a pool of more than $200 million in annual federal grants.

More than 310 colleges have HSI status, a distinction that requires a student body that's at least 25 percent Latino, said Antonio Flores, president of Hispanic Association of Colleges and Universities.

SRJC officials said it will take several years to reach and sustain the population threshold required to become an HSI, and even then it would be of uncertain benefit. As an average of eight additional institutions qualify each year, the competition for the grant money becomes more intense.

But looking at the pipeline of students feeding SRJC, one thing is certain. It seems only a matter of time before the school surpasses the 25 percent enrollment threshold.

According to SRJC's Office of Institutional Research, the proportion of 12th graders in Sonoma County who are Latino will go from 32.8 percent next year to 42.8 percent in 2021.