Outbreaks of plague were not particularly unusual events in London; major epidemics had occurred in 1592, 1603, 1625 and 1636. Furthermore, Pepys was not among the group of people who were most at risk. He did not live in cramped housing, he did not routinely mix with the poor, and he was not required to keep his family in London in the event of a crisis. It was not until June 1665 that the unusual seriousness of the plague became apparent, so Pepys's activities in the first five months of 1665 were not significantly affected by it. Indeed, Claire Tomalin writes that "the most notable fact about Pepys's plague year is that to him it was one of the happiest of his life." In 1665, he worked very hard, and the outcome was that he quadrupled his fortune. In his annual summary on 31 December, he wrote, "I have never lived so merrily (besides that I never got so much) as I have done this plague time". Nonetheless, Pepys was certainly concerned about the plague. On 16 August he wrote: