Simplify the following text for a Grade 8 native English-speaking person.
Original: In the Gregorian calendar , it is the 2011th year of the Common Era and the Anno Domini designation ; the 11th year of the 3rd millennium and of the 21st century ; and the 2nd of the 2010s decade .
Simplified: It is the 2011th year in the Common Era ( or Anno Domini ) , and the 11th year in the 3rd millennium and 21st century .