That represents 4 days worth of household CO2 production!
(628/150 = 4.18 days of household CO2 production)
1 Day = 150 lbs of CO2 per U.S. household – excerpt from the March 2009 issue of National Geographic Magazine titled Saving Energy – It Starts at Home. The images above are from the article. You can also get them at National Geographic Wallpapers.