By Michael Martinez and Mariano Castillo, CNN

Los Angeles (CNN) - Jonathan Larios hears it all the time: Someone walks into his Honduran restaurant and they think it's a Mexican place.

"Oh, I hate that. That bothers me a lot," said Larios, 21, general manager of two Los Angeles-area restaurants called Honduras Kitchen. "They always ask, 'How's the Mexican food?' It gets frustrating over time.

"It's like the most race that people always see is black, Mexican and American. They don't see anything else," said Larios, whose mother is Honduran and father Salvadoran.

His first-hand experience shows that some Americans confuse all Hispanics as being Mexicans. While it's true that Mexicans make up the largest segment of the Hispanic population in the United States, a new Brown University study that shows Latinos are hardly a monolithic group.

The demographic has wide differences in nationalities that are becoming more salient, the study said.

"When studies are done of Hispanics, the results mostly reflect the experience of Mexicans, who are more than 60% of the total," the study says. "But observers would be mistaken if they thought they knew Hispanics in the U.S. by looking only at Mexicans."

The large percentage of U.S. Hispanics of Mexican descent, an overwhelming majority, inadvertently hides distinct trends among Hispanics with origins in other countries, according to the report released Wednesday.

The differences extend to cuisine, too, Larios added.

His parents own both restaurants, in Long Beach and Huntington Park, the latter being in business for 20 years, making it the oldest Honduran eatery in the state, he said.

"I tell them our food is very different," he said of customers who confuse Honduran food with Mexican dishes. "Most of our food doesn't have anything hot and spicy. Our food will never be spicy."

Hondurans are proud of their heritage and often emblazon the flag on their soccer jersey, whether they're playing in a neighborhood league or cheering for the national team, he said.

Many non-Mexican groups are growing at a faster rate, and doing better economically, the study found. In another telling figure, Hispanics other than Mexican are much less segregated than often assumed.

While the number of Hispanics who identify as Mexican has increased 137% between 1990 and 2010, those with other origins have grown at a much faster rate. During that 20-year span, it is estimated that the Honduran population in the U.S. increased by 383%, Guatemalans by 289% and Peruvians by 204%.

"Mexicans are not losing their weight, but some groups who were small and not on the radar now number in the millions," said John Logan, one of the report's authors. "South Americans are now everywhere, and if you add them up, they are a huge number."

The three largest groups of Hispanics - Mexicans, Puerto Ricans and Cubans - make up 62%, 9%, and 4%, respectively, according to Census data. Central Americans make up 8% of the Hispanic population, and South Americans 5%.

In 1990, only three Hispanic largest groups had more than a million residents in the United States. By 2010, Dominicans, Guatemalans and Salvadorans had joined that club.

One of the findings seemed to show that the national perception of the Hispanic population is closely tied in with the Mexican community. There is the persistent idea, for example, that Hispanics in the United States are insular and segregated from other non-Hispanic communities.

"The very stable trend of high segregation is one attributed to Hispanics, but it turns out it is mainly a characteristic of Mexicans," Logan said.

According to a measure known as the Index of Dissimilarity, every Hispanic group except Mexicans has become substantially less segregated since 1990.

Half of all South Americans used to be located in Los Angeles, New York and Miami, but by 2010, only 34% lived in these cities, the study says.

Other generalizations persist.

"There may be a general assumption that Hispanics are immigrants, which was never true for Puerto Ricans," Logan said. "There may be a generalized assumption about relatively low education and skill levels, which does not fit average Cubans and South Americans, and increasingly not Puerto Ricans."

The data indicates that below the surface, there is a great deal more change within the Hispanic population than commonly thought, Logan said.

These differences could be important to advertisers who target Hispanics, or politicians who seek their votes.

"I suspect that on the whole, their view of the Hispanic community is that of it as one community (the Mexican community) and that's probably not a strategy that will be really helpful," Logan said.

Logan conducted a similar study in 2000, and his most recent research was a continuation of that to see if the differences he spotted 13 years ago remained. The patterns and trends have become even clearer in the past decade, he said.

The report also took a look at certain social and economic characteristics of the different groups that showed various degrees of economic success. One measure examined were the median wages of each group.

While the median annual wage for Mexicans in the United States was $20,200, wages were much higher for Argentines and Venezuelans, both with median wages of $30,300.

This finding wasn't surprising, as social scientists have long noted that those with roots in Cuba and South America tend to have different economic backgrounds.

But one group that is sometimes assumed to be insular and employed in lower wage jobs, Puerto Ricans, are actually doing quite well, the study found. Puerto Ricans have increasingly integrated with the rest of the population and have a median wage of nearly $30,000.