It depends on the era... I started listening to metal in the early 90's, when it seemed to be at it's height in popularity. When I started going to high school in around '97-'98 metal was dying in a very big way. Less & less people were listening to it, to the point where it became uncool to listen to it. Also, a lot of bands from late the 80's/early 90's became very instrumental in setting the foundation of continued interest in the society. On the other hand, if you just look at things over the last 3 years I think metal has got much more popular in the last 3 years, but it is still far from being mainstream. Because of this immediate slight "surge" in popularity I voted the 3rd option.