Among the bodegas and cafes in the throbbing heart of the city, Miami Dade Community College is bursting at the seams.

The largest higher education institution in the US, with about 165,000 students, it teems with people from different backgrounds. Students come from 192 countries and speak 93 languages. Most work full time while enrolled and are the first in their families to go to college.

"We're serving a population that the (four-year) universities refuse to serve," said Eduardo Padron, Miami Dade's president.

Long considered the poor relation of US higher education, the nation's 1,000 public community colleges - two-year institutions that grant associate's degrees or professional certificates - are at the centre of President Barack Obama's plan to raise the proportion of the population who graduate to the highest in the world by 2020. In the past ten years, the US has fallen to 15th place in this measure, with 39 per cent of 25- to 34-year-olds having a post-secondary degree.

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Mr Obama has announced a $12 billion (?7.3 billion) plan to double the graduation rate from colleges. Three quarters of the cash will fund programmes to improve dismal graduation rates - only 12 per cent earn a degree in the expected time. Most of the rest will pay for renovations to neglected infrastructure.

The plan is about more than bragging rights, Mr Obama said, as he announced the details at a community college in Michigan, where employment in manufacturing has all but disappeared.

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"We know that in the coming years, jobs requiring at least an associate's degree are projected to grow twice as fast as jobs requiring no college experience," he said. "We will not fill those jobs - or keep them on our shores - without the training offered by community colleges."

The cash could not come at a more critical time. Sharp cuts in spending on public four-year universities, plus soaring tuition fees at private ones, have forced more students into community colleges, which have also faced budget cuts but generally are not allowed to turn applicants away.

Some, including Miami Dade, where enrolment has risen 14 per cent in the past two years, have announced admission limits for the first time in their history.

"Students who don't get into the universities come to places like Miami Dade because they think we have room," said Ophelia Somers, president of the Student Government Association. In fact, Miami Dade's facilities are 40 per cent over capacity, and as many as 60 students are packed into each seminar-style class, forced to wander the corridors to find spare chairs.

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Jill Biden, wife of Vice-President Joe Biden, teaches at a community college near Washington. She gave a preview of Mr Obama's plan to the United Nations Educational, Scientific and Cultural Organisation's World Conference on ³ÉÈËVRÊÓƵ in Paris recently.

She called community colleges one of America's "best-kept secrets". Yet while they account for more than 33 per cent of US enrolment, traditionally they have received just 10 per cent of the funding awarded to four-year public universities.

The proposals must be ratified by Congress to take effect.

"Community colleges are underestimated," Ms Somers said. "But we truly represent the fact that everybody deserves the right and the privilege to learn."

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