1 Jul 1972 to 1 Mar 1974
US foreign surface letter rate 15 c
Swedish foreign surface letter rate 100 öre
US handstamp shows amount to pay in US cents (normally double deficiency) and US surface letter rate.
In Sweden the indicated fraction multiplied by 100 rounded up to nearest 5 öre was normally paid by affixing stamps on the item.

Letter with 11 cent. Correct rate 15 cent. Shortpaid 8 cent. US due handstamp indicates double deficiency 8 cent and foreign letter rate 15 cent. 8/15 of 100 öre = 53.33 rounded up to 55 öre have been charged in Sweden. Letters with air mail stamps were normally regarded and charged as air mail, but there was a rule saying that items with less than 75% of the the combined airmail postage should be sent as surface mail. This item has therfore been charged as surface mail