I don't know if the US Census data for the State of Khalifornia would be considered more reputable than the estimations or assumptions of a anti-immigration lobby group.

Foreign borns make up about 35 percent of California’s adult population but represent only about 17 percent of the state's prison population.

U.S. born adult men are incarcerated in California state prisons at rates up to 3.3 times higher than foreign-born adult males.

Among men ages 18-40 – the age group most likely to commit crime – those born in the United States are 10 times more likely than immigrants to be in county jail or state prison.

Noncitizen men from Mexico ages 18-40 – a group disproportionately likely to have entered the United States illegally – are more than 8 times less likely than U.S.-born men in the same age group to be in a correctional setting (0.48% vs. 4.2%).

California cities with a higher share of recent immigrants have lower property and violent crime rates than in those with fewer immigrants.

2007 Study by Center for the Continuing Study of the California Economy

The CCSCE study determined that of the estimated 3 million illegal immigrants in California, about 1.8 million are employed, a rate of employment substantially larger than the population as a whole, incidentally. It points out that only about 800,000 Californians are listed as unemployed, "so even if every unemployed worker were ready and willing to fill a job left by an unauthorized immigrant … there would be a large shortfall in California." Eliminating illegal immigrant workers, in short, would be a serious blow to the California economy, leaving at least a million jobs vacant.