1968 Mexico Summer Olympics

1. RWANDA

3 stamps from the set of 4

2. PARAGUAY

5 stamps of the set of 9: Olympic medalists

3. ECUADOR

3 stamps of the set of 8:

1972 Munich Summer Olympics

PARAGUAY

The set of ten( I only have seven stamps so far) depicts the Decathlon and ten Olympic Gold medalists at this discipline.
The ten events are: 100 meters, Long jump, Shot Put, High Jump, 400 meters, 110 meters hurdles, Pole Vault, Discus, Javelin, 1500 meters.