In the main body of the paper they say "We find that distinctively Black names reduce the likelihood of employer contact relative to distinctively white names by 2.1 percentage points, an effect equal to 9% of the Black mean contact rate".

I think we take that to mean that it's an absolute 2.1% reduction, and if it's also 9% relative reduction, then that would have black applicants getting a response 23.3% of the time, and white applicants 25.4%.

Statistically speaking, it could be a due to randomness, but that depends on the test statistics. I'd check the maths if I had any doubt about the conclusion ;)

It’s 25.1% vs. 23.0% response rates. Table 1.

It's 2.1 percentage points which they say is about a 9% difference.

from the paper:

>> "an effect equal to 9% of the Black mean contact rate"