An additional 34percentt were classified as Level 2, with just marginally higher skills.
The tornado has been classified as level 3 on the Enhanced Fujits (EF) scale.
Three were classified as "level one" trauma, he said, meaning they had been shot either in the head, neck, torso, knee or elbow.
The Chernobyl explosion was the world's worst nuclear accident and is the only one classified as level 7 on the International Nuclear Event Scale.
Hospitals' perinatal services were classified as level 1, 2, or 3 (level 3 refers to tertiary referral centers).
That rate was the highest for any state of what the study classified as Level 1 literacy, the lowest of five possible levels.
The majority of the images were classified as level one with others at level two and three.
Under the INES, Three Mile Island is classified as Level 5, an accident with wider consequences, whereas both Fukushima and Chernobyl are Level 7, major accidents.
Investments that are classified as Level 2 within the fair value hierarchy account for approximately 92percentt of US banks' fair value assets.
For the top ten banks, 16% of securities were classified as "Level 3", equivalent to 1.5 times their equity (see chart).
Classified as Level 4 buildings, they would generally be more than 150,000 square feet in size and likely to house law enforcement and intelligence agencies deemed to be at high risk of attack.
