It's not so little that it's a pittance. Use the SS calculator below, entering the "age you stop working" as the age when you complete your 10 years of SS contributions (to simulate leaving the US upon completing those 10 years).
http://www.ssa.gov/retire2/AnypiaApplet.html
It depends on how you define pittance.
This is how they compute your retirement benefits:
Step 1- We determine the number of years of earnings to use as a base. If you were born after 1928, that base number is your
35 highest years of earnings. Fewer years are used for people born in 1928 or earlier.
Step 2- We adjust the earnings in these years for wage inflation. We call this "indexing."
Step 3- We determine your average adjusted monthly earnings based on the number of years in step 1. (
If you don't have earnings in 35 different years, some years with $0 earnings will be used to figure this average amount.)
Step 4- We multiply your average adjusted monthly earnings by percentages in a formula that is set out by law. If you turn 62 in 2007, that formula adds together:
90 percent of your first $680 of average monthly earnings,
32 percent of the amount between $680 and $4,100, and
15 percent of everything over $4,100 to give you your full retirement benefit amount. (If you start your benefits before you reach full retirement age, this amount will be reduced.)
If you become disabled or die before you reach full retirement age, we may use fewer than 35 years of earnings to calculate your average monthly earnings, but the same basic formula is still applied to figure your benefit amount.
You also can go to our Benefits Planner and use the earnings shown on your Statement to calculate your estimates yourself.
Simple: The problem is that if you worked for only 10 years you will have twenty five years of zero earning factored into your calculation. This will seriously pull down your benefit amount.