Black-white age differences among Pulitzer Prize for Poetry winners

I was taking a look at Pulitzer Prize for Poetry winners. It turns out that there's a notable age gap between black recipients and everyone else. Since 1980, the average age of the forty-four Pulitzer Prize winners was fifty-eight. (There were two winners in 2008). 

The average age of white poets when they received the prize is 60, and the average age of the seven black recipients is 44. Over the last forty years, W.S. Merwin was the oldest, at 82, when he won the Pulitzer in 2009. Rita Dove was the youngest, at 35, when she won the award in 1980. 

What difference does it make that black poets tend to win at much earlier ages than white poets? Really, there are too few black poets to make an adequate comparison. Still, it's worth considering whether major awards and support in general arrives at different stages in the careers of white and black poets.

Only 6 white poets were under 50 years old when they earned the Pulitzer. By contrast, only one black poet was over the age of 50. 

I wonder if there are structures in place to support larger numbers of young black poets than somewhat older poets. Natasha Trethewey and Tracy K. Smith, the youngest recipients of Pulitzer Prizes for Poetry, at 41 and 40, respectively, in the twenty-first century, began their professional careers as recipients of the Cave Canem Poetry Prizes. Each of the African American winners of the Pulitzer previously participated in Cave Canem.   [Correction: I meant to say, the African American winners in the 21st century. But as noted below in the comments, two folks did not participate before winning the award.]

Related: 

• Tyehimba Jess wins Pulitzer Prize for Poetry

• Margaret Walker almost won the Pulitzer in 1943

• Does the Pulitzer award for poetry favor "younger" black poets?