Global surface temperatures increased at a rate of near 0.11°F/decade (0.06°C/decade) during most of the twentieth century, but the rate increased to approximately 0.29°F/decade (0.16°C/decade) during the past 30 years. There have been two sustained periods of warming, one beginning around 1910 and ending around 1945, and the most recent beginning about 1976. The decade 2000–2009 is the warmest on record with an average global surface temperature of 0.96°F (0.54°C) above the twentieth century average. The following chart indicates the top ten warmest years: