Hook and his father both mention that it's been about a century between when Hook was a child and their meeting that Regina arranged. However, the show has previously established that Rumplestiltskin, who Hook knew when they were both mortals, has been the Dark One for about 300 years.
When all the Dark Ones, Snow, David, Henry, Regina, Robin and Gold are gathered in the lake so the boat can take the living to the Underworld, there are more Dark Ones than living people. More Storybrooke people should have been there. Also, the Dwarfs, who had been clearly marked by the Dark Ones, are not there either.