TV’s first African-American Bachelorette star, Rachel Lindsay, has sparked a 72% jump in black viewership for ABC’s summer reality series. But through the first three episodes, the show’s white audience is down 19%. That falloff mirrors a general decline in ratings for summer reality shows. But it also illustrates an increasing fragmentation among viewers of different races and ethnicities.

Nielsen data for 2017 to date, analyzed by USA TODAY, shows that no single program is ranked in the top 5 among whites, blacks, Asian-Americans and Hispanics, (Two, AMC ‘s The Walking Dead and NBC’s This Is Us, were among the most popular for three of those groups).

Why the disparity? Analysts say that in recent years, amid dramatic growth in the amount of TV and streaming content, programmers have accelerated their diversification efforts, targeting narrower niches. African-Americans watch far more TV than any other group — nearly 44 hours a week last fall, Nielsen says — while Asian-Americans watch the least (less than 15 hours).

“The population has become much more diverse, so networks realize that and have targeted specific groups with shows they think they’ll watch,” says media consultant Brad Adgate, a former ad-firm researcher.

In a fragmented media environment with fewer hits, “If you can create a TV show that really resonates with a specific ethnic group, you can aggregate a large-enough audience within that group to make it a successful show” with help from social-media sharing, says Chris Fosdick, a principal at Cambridge Group, a Nielsen-owned consultancy.

Big-tent reality shows such as NBC’s summer hit America’s Got Talent and its new companion, World of Dance, inherently diverse, tend to be more popular across different viewer segments. But preferences diverge when it comes to dramas,and black viewers prefer shows featuring black characters such as ABC’s Scandal and Fox’s Lethal…