Complex sentence: The natural increase since the last census was 1,155,182 people (1,948,398 births minus 793,216 deaths), immigration from outside the United States resulted in a net increase of 663,161 people, and migration within the country produced a net increase of 218,722 people.
Split into simpler sentences: The natural increase since the last census was 1,155,182 people (1,948,398 births minus 793,216 deaths). Migration within the country produced a net increase of 218,722 people.