1920-1940
The average US child was potty trained at 12 months old
1940-1960
The average US child was potty trained at 18 months old
1960-1980
The average US child was potty trained at 2 years old
1980-1990
The average US child was potty trained at 2.5 years old
1990-Present
The average US child is potty trained at 3 years old
