What is the number one type of complaint that the EEOC receives?

The Equal Employment Opportunity Commission (EEOC) is charged with handling and investigating various types of discrimination complaints, ranging from race, age, ethnicity, and gender, to other protected class issues.  Yet, none of these claims represents the number one type of complaint received by the EEOC.  What is the number one type of complaint?  Retaliation.  This is a good reminder for employers that not only is retaliation prohibited, but it is often of equal or more concern than the underlying complaint of discrimination.