The bar graph above shows total annual carbon dioxide emission levels in Japan for the five year period from 2008 through 2012. Emission levels are measured in kilograms per kilowatt hour.
Emissions were highest in the 2008, the first year shown, at 750 kg/kWh. Emissions in 2009 dropped a small amount, to roughly 700 kg/kWh. The following year, 2010, total carbon dioxide emission was at approximately the same level.
In 2011, the emission level dropped to its lowest point on the graph, dipping to around 600 kg/kWh. The level of emissions rose very slightly in 2012, the final year.
Overall, annual carbon dioxide emissions in Japan decreased after 2008, although the downward trend did not continue through the final year, 2012. From the first year shown to the last, the annual level of carbon dioxide emission decreased approximately 150 kg/kWh, or roughly twenty percent from the 2008. Most of this decrease occurred between 2010 and 2011.