I already answered that. The market has grown immensely, but all the growth is from ethnic groups and non-Hispanic whites are down to about 40% and shrinking in 18-49 age groups.
I've spoken in the past with two friends who programmed rock stations in Dallas, and both agree that the rock segment is much smaller today than it was 20, 30 and 40 years ago. There are fewer non-Hispanic white men in the younger demos who listen to rock at all, and in the full 18-49 range the group of non-Hispanic whites has not grown and is now about half the percentage of the market it was 20 years ago.