It's actually probably safer today that in the past because there's a lot more regulations that have sprouted up due to accidents in past decades. For example, there was a fire at a haunted castle at Six Flags Great Adventure in 1984 that killed eight teenagers. The building didn't even have a sprinkler system, no fire drills, the wall was made of inflammable material. But due to that tragedy, there's been so many rules and restrictions passed where something like it could never happen again. There was another accident, I think in California, that caused an organization to start that would regulate all the rides to make sure they were safe.
Also, a lot of ride accidents are caused by the guests' own negligence.