A new 15-cent stamp goes into use in 1978 after being approved by the Postal Rate Commission. The American Medical Association also concludes a 14-year study showing that cigarette smoking causes heart disease and may cause cancer.

Elsewhere that year:

• President Carter signs a law making 70 the mandatory retirement age for most Americans.

• Star Wars becomes the all-time leader in worldwide film rentals — it takes in $202 million, surpassing the previous record-holder Jaws.

• The Federal Communications Commission (FCC) studies children’s television to see if the TV industry is showing a reasonable amount of children’s shows, including educational programming.

• The Senate ratifies two new Panama Canal treaties: One gives Panama full control of the Canal at the end of 1999; the other gives the United States the right to defend the Canal’s neutrality.

• Military officers seize power in Afghanistan.