Kidnappings, sexual assault, and children

Are kidnappings and sexual assaults of children more prevalent now than they were 50 years ago? Does it just seem more prevalent because of the media's focus on it? It feels like it is so hard to protect our children nowadays. I know, as a parent, I have a hard time letting my children do things and go places. I worry about what could happen to them. Is that just being an overprotective parent or is this justified on how our society is spinning out of control?