Hmm, I think their stats are a little off, at one point in the video Encina said something like "1-2% of the population have DID, so that means between 75 and 150 million people have been diagnosed with a dissociative disorder." The 1-2 % of the population figure seems the figure that is most often used, but saying that percentage of the population are estimated to have a dissociative identity disorder and saying 1-2% of the population have been diagnosed with the disorder are two very, very different things. Most likely only a very small fraction of the people who are estimated to have DID ever get formally diagnosed with it. But yes, it seems that 1-2 % figure is the most frequently used estimate of the prevalence of DID. It is not a rare thing.