Claim: On June 26, 1964, Swiss Post introduced postal codes with four digits and divided into nine postal districts as the third country after Germany (1941) and the United States (1963).
Evidence: On 26 June 1964, Swiss Post introduced postal codes as the third country after Germany (1941) and the United States (1963). In Switzerland, the postal codes have four digits. Switzerland is divided into nine postal districts, numbered from west to east.