My RYM stats tell me..
A large majority of the music I listen to is from the last 30 years. I guess that's considered new music, I haven't got around to listening to prehistoric stone cylinder recordings of cavemen banging on animal skins.
One of the reasons why I don't listen to as much 60's and 70's music is because I find it more difficult to relate to. I've never lived in those decades and never had any desire to. The reason why the average rating is higher is probably because I take less risks when it comes to older music. It's easier to know what albums are highly regarded and what I might have a greater chance of enjoying. While with the 00's and 10's I've been consuming music in real time, I've had to take more risks to sort the good from the average.