El Salvador is about 103 times smaller than Greenland.

Greenland is approximately 2,166,086 sq km, while El Salvador is approximately 21,041 sq km, making El Salvador 0.97% the size of Greenland. Meanwhile, the population of Greenland is ~57,792 people (6.5 million more people live in El Salvador).
Tip: This to-scale comparison of Greenland vs. El Salvador uses the Mercator projection, which distorts the size of regions near the poles.