By the end of 1964, the Philadelphia Mint had struck 273,304,004 Kennedy Half Dollars, while the Denver Mint struck 156,205,446 coins. Additionally, the Philadelphia Mint struck 3,950,762 Kennedy Half dollars in Proof format, for sale to collectors within the 1964 Proof Sets. All of these numbers were significantly higher compared to the numbers from the previous Franklin Half Dollar series. In fact, the total number of 1964 Kennedy Half Dollars was not far off from the entire output of Franklin Half Dollars for all years of the series from 1948 to 1963.
It is not difficult to determine the reason why the mintage of the 1964 Kennedy Half Dollar was at such a high level. The recently deceased President had been extremely popular during his lifetime, and the public was incredibly saddened by assassination. When the first coins bearing his portrait were released to the public, they were quickly hoarded and even traded at a premium despite the hundreds of millions which would eventually be released. This activity leads to a relatively high number of 1964-dated half dollars remaining available to collectors, even in uncirculated condition.
The 1964 Kennedy Half Dollar also holds distinction as the final half dollars struck for circulation within the composition of 90% silver and 10% copper. Due to a rising market price of silver, the Mint reduced the silver content of the half dollar to 40% the following year, and then removed the silver content altogether after 1970. This has also increased popularity of the 1964 Kennedy Half Dollar, which trade for a premium in circulated grades based on the value of the silver content.