California in 1982 is much more Hispanic than it was when it was ceded to the United States by Mexico in 1848.
And, according to a report just issued by the Center for Continuing Study of the California Economy, that Hispanic population -chiefly Mexican in origin - will increase dramatically in the remaining years of the 20th century.
Even if the US manages to tighten its leaky southern border, the rate of increase will be high, according to the center's analysts.
Presenting ''low'' and ''high'' alternative projections - based on different assumptions about total immigration into California in the 1980-2000 period, the amount of illegal Hispanic immigration, and birthrates for Hispanic women - the report concludes that the Hispanic population in the state will be 24.4 (low) or 28.1 (high) percent of the total in 2000, compared with the current 19.2 percent.
Putting it another way, the report projects the 1980-2000 growth rate of the Hispanic population in California at 69.7 (low) or 96.5 (high) percent, compared with 33.3 and 34.4 percent for the total population and 20.6 and 32.7 percent for the ''Non-Hispanic Whites,'' who at present comprise 66.6 percent of the total population.
The number of people of Hispanic origin in California recorded by the US Census of 1980 was 4.5 million - 19.2 percent of the state's total population. The report projects a state population of from 31.5 to 31.8 million by 2000 (the 1980 census recorded 23.7 million). Hispanic population in the year 2000 is projected at from 7.7 million to 8.9 million.
Stephen Levy, senior economist for the center, writes in the report: ''The growth of Hispanic population in California in the next 20 years may be substanially affected by how the current national debate on immigration policy is resolved. . . . There is concern about the implications of immigration on the nation's economy and on the environment and quality of life. . . .''
More than 10 percent of Americans live in California, the most populous state. New York is a not-very-close second at 17.5 million and Texas third at 14 .2 million.
Of the four states that have experienced the greatest influx of Hispanic immigrants, legal and illegal, California in 1980 had 4,543,770; Florida, 857, 898; New York, 1,659,245; and Texas, 2,985,463. Other states with significant Hispanic populations are Arizona, 440,915; Colorado, 339,300; New Mexico, 476, 089.
Another major population trend cited in the report is the rapid increase of Asians in California. By 2000, according to projections, they will overtake blacks as California's No. 2 minority group. In 1980 blacks comprised 7.5 percent of the state's residents, Asians 6.7 percent; for 2000, the report cites low immigration-high immigration figures of 7.6 percent or 7.1 percent blacks and 9.8 percent or 10 percent Asians.
At one point the report states that, assuming the state's ''share of illegal immigrants'' was equal to its average share of legal Mexican immigrants in the 1975-1979 period, ''California is projected to receive 47.7 percent of projected illegal immigrants into the US.''
Robert K. Arnold, director of the Center for Continuing Study, notes that the report assumes vigorous growth of the California economy over the next two decades. In spite of the current recession, he and most California economists continue to expect that the state will not only experience strong economic expansion in coming years, but also will lead the nation in this respect.
That being the case, says Dr. Arnold, California should have no difficulty absorbing and providing jobs for the increased numbers of Asians, Hispanics, and other migrants from within and without the US. He points out that most of the immigrants from Mexico and other Latin American countries fill ''service'' jobs, at least initially, and that this sector is expected to experience greater growth than most others over the next 20 years.
Major population groups in California - 1980 to 2000 1980 1985* 1990* 1995* 2000* Low alternative Hispanic 19.2% 20.7% 21.7% 23.2% 24.4% Non-Hispanic white 66.6% 64.2% 62.5% 60.2% 58.2% Black 7.5% 7.6% 7.7% 7.6% 7.6% Asian and other 6.7% 7.5% 8.1% 8.8% 9.8%
High alternative Hispanic 19.2% 21.6% 23.6% 25.9% 28.1% Non-Hispanic white 66.6% 63.2% 60.6% 57.6% 54.8% Black 7.5% 7.4% 7.4% 7.2% 7.1% Asian and other 6.7% 7.8% 8.5% 9.3% 10.0% * Estimates Source: Center for Continuing Study of the California Economy, Palo Alto, Calif.