Other factors tied to increased autism risk, though to a lesser degree, included congenital malformations, breech and other kinds of abnormal birth positions, multiple birth, a low 5-minute Apgar score, weighing less than 5.5 pounds at birth, umbilical cord complications, fetal distress, being small for gestational age.
SILVER vs CLAD: Some of the Eisenhower Dollars issued between 1971 and 1976 were composed of 40% Silver. These were Special Issues available only from the U. S. Mint which sold them at a premium. Eisenhower Dollars issued for general circulation were Clad: composed of a mixture of nickel and copper. D (Denver): The 'D' mint mark is located on the obverse between the date and Eisenhower's neckline. S (San Francisco): The 'S' mint mark is located on the obverse between the date and Eisenhower's neckline. Note: Dollars struck in Philadelphia bear no mint mark.
Until 1980, coins minted at Philadelphia bore no mint mark, with the exceptions of the Susan B. Anthony dollar and the wartime Jefferson nickel. In 1980, the P mint mark was added to all U.S. coinage except the cent. Until 1968, the Philadelphia Mint was responsible for nearly all official proof coinage.