Simplify the following text for a Grade 15 native English-speaking person.
Original: The Defense Intelligence Agency ( DIA ) is a key member of the Intelligence Community of the United States , and is a major producer and manager of military intelligence for the United States Department of Defense , employing over 16,500 military and civilian employees worldwide .
Simplified: The Defense Intelligence Agency , or DIA , is a major producer and manager of military intelligence for the United States Department of Defense , employing over 11,000 military and civilian employees worldwide .