The Eighth Report of Fukushima Prefecture Health Management Survey was released on September 11, 2012.

The thyroid examination section of the survey is shown in this link.
http://www.pref.fukushima.jp/imu/kenkoukanri/240911siryou2.pdf 
 
It contains new thyroid examination results from the first five months of Fiscal Year Heisei 24 (FYH24), from April 1 through August 24, 2012. The results revealed that 18,358 (43.12%) of 42,060 children, mostly from Fukushima-city, Fukushima, had thyroid ultrasound abnormalities. Together with 38,114 children (13,645 or 35.8% had thyroid ultrasound abnormalities) tested in the last half of Fiscal Year Heisei 23 (FYH23) from October 2011 through March 2012, a total of 32,003 (40.0%) of 80,174 Fukushima children have been found to have ultrasound abnormalities....