Information from www.marketwatch.com

Over 9 in 10 Americans are affected by the Social Security system, and there are over 34 million retired persons receiving benefits. The importance of Social Security cannot be overstated.

For one-in-five retirees, Social Security is their only source of income. For one-in-three retirees, Social Security is 90% of their retirement income. For two-in-three retirees, Social Security is more than 50% of their retirement income. What you don’t know about the system can hurt you.

Social Security benefits are based on your past earnings. Benefits are skewed in favor of lower-paid individuals. The SSA uses 35 years of earnings to calculate your monthly benefit.

The earnings test only applies to those younger than full retirement age. The earnings test lowers benefits in the current year, but doesn’t take them away.

You may be eligible for three different types of benefits (but not at the same time). As a general rule, if you worked and paid Social Security taxes for more than 10 years you will be eligible for the “worker’s benefit.” If you are married, you may also be eligible for a “spousal benefit.” Finally, if your spouse dies you may be eligible for a “survivor benefit.”

Benefits are adjusted for inflation whether or not you start your benefit.

A divorced spouse qualifies for spousal or survivor benefits if marriage lasts 10 years or more.

You can monitor your Social Security account online. From 1999 to 2011 the Social Security Administration mailed Social Security Statements to anyone who was 25 or older. In May of 2012 they stopped these automatic mailings and went online to save money. They will resume mailings every five years (ages 25, 30, 35, etc.) starting in September. However, the online statement that’s created by you in the “my Social Security” section of their website might be your best option to track retirement.