Please answer the following question: Given the following passage  "According to a study by Dr. Paul Brest, Hispanics or "Latinos" include immigrants who are descendants of immigrants from the countries comprising Central and South America. In 1991, Mexican Americans, Puerto Ricans, and Cuban Americans made up 80% of the Latino population in the United States. Latinos are disadvantaged compared to White Americans and are more likely to live in poverty. They are the least well educated major ethnic group and suffered a 3% drop in high school completion rate while African Americans experienced a 12% increase between 1975-1990. In 1990, they constituted 9% of the population, but only received 3.1% of the bachelors's degrees awarded. At times when it is favorable to lawmakers, Latinos were considered "white" by the Jim Crow laws during the Reconstruction. In other cases, according to Paul Brest, Latinos have been classified as an inferior race and a threat to white purity. Latinos have encountered considerable discrimination in areas such as employment, housing, and education. Brest finds that stereotypes continue to be largely negative and many perceive Latinos as "lazy, unproductive, and on the dole." Furthermore, native-born Latino-Americans and recent immigrants are seen as identical since outsiders tend not to differentiate between Latino groups.",  answer the following question. Note that the answer is present within the text.  Question: What was the time frame where Latino rates fell and African American rates rose for high school completion?
Answer:
1975-1990