The gestation period for an elephant is 640 to 660 days. This is equivalent to about 95 weeks, or 22 months, and is the longest gestation period of any mammal.
Dimes dated after 1964 are copper-nickel clad and contain no silver. Quarters are also clad, except for the bicentennial commemorative coins with an S mint mark that were produced for mint and proof sets. Kennedy half dollars from 1965 to 1970 were 40 percent silver composition. After 1970, all Kennedy halves were clad, except the same S bicentennial issue.
Confidence votes 4.3K. 1964 was the last year the US minted dimes and quarters from silver for regular circulation. The US Mint makes proof sets every year that have silver coins in them, which you can buy from the US Mint or a local coin dealer. Also, look out for silver halves, which were last made in 1964 as well at 90% silver.