The entry goes on to say, "In 1937, Austria issued two 'Christmas greeting stamps' featuring a rose and zodiac signs. In 1939, Brazil issued four semi-postal stamps with designs featuring the three kings and a star, an angel and child, the Southern Cross and a child, and a mother and child. In 1941 Hungary also issued a semi-postal whose additional fees were to pay for "soldiers' Christmas". The first stamps to depict the Nativity were the Hungary issue of 1943. These were all one-time issues, more like commemorative stamps than regular issues.
"By the 1990s, approximately 160 postal administrations were issuing Christmas stamps, mostly on an annual basis. Islamic countries constitute the largest group of non-participants, although the Palestinian Authority has issued Christmas stamps since 1995."
For more on Christmas stamps, click here.