My first thought about anything like this... Quality of the data set... This is based on self-reported data. Is it not also worth asking if it has become more

My first thought about anything like this... Quality of the data set... This is based on self-reported data. Is it not also worth asking if it has become more socially acceptable to admit to having sex less often (or not at all)? Just as it probably has become more socially acceptable to not be in a relationship...