1 May 1975 - 31 Dec 1975
US foreign surface letter rate 18 c
Swedish foreign surface letter rate 110 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 110 and rounded up to nearest 5 öre was normally paid by affixing stamps on the item.
Second rate air mail letter with 26 cent. Correct
rate 52 cent. Shortpaid 26 cent. US due handstamp indicates double deficiency
52 cent and foreign letter rate 18 cent. Swedish due 52/18 of 110 = 317.78
öre rounded up to 320 öre has been charged. The amount has probably
been paid together with other fees.