- Total Population is based on decennial census data from the U. S. Census Bureau. The annual intercensus estimates were mathematically interpolated from the Census Bureau’s decennial data.
- The Actual Number of Representatives is the number authorized by Congress to represent the state. Note that the actual number representing the state at any given time may be a smaller due to vacancies (e.g., resignations, deaths, removal). Conversely, the total number of Representatives during any time span may be more than the authorized number due to turnover. The initial point in the graph is the first year that the state is admitted to the union
- The District Population Size is the total resident population (per the U. S. Census Bureau) divided by the total number of House Representatives actually authorized by Congress (by year for each state).
- The Minimum House District Size was established by the U. S. Constitution at 30,000 inhabitants.
- This is the hypothetical Maximum Number of House Representatives that could have been allocated to the state. This equal to the state’s total population divided by 30,000. For each decennial apportionment, this calculation is done in the ninth year of the decade (e.g., 1989) and is applied to the decade beginning the third year of the following decade (e.g., 1993 to 2002).