tights trends

has anyone else noticed tights seem to becoming less opaque? a year or two ago everyone was wearing really thick (like 80/100 denier) opaque tights but now most people are wearing thinner semi-opaques/nylons like 15/30 denier and you dont see people wearing thicker ones much any more. i wear pretty much every day as i tend to wear dresses/skirts and dont like bare legs. has anyone else noticed this? i've seen it in winter as well so its not just a summer thing