11.   Huge population shifts and natural catastrophes over scores of thousands of years make a prehistoric linguistic unity improbable and, in any case, untestable.

12.   It is now in a period of rapid population shifts, as immigrants from Mexico, Latin America and Asia flood into the state.

13.   Monthly declines in the civilian labor force are not unusual and can be caused by population shifts or a jump in the number of people who retire.

14.   Population shifts due to changing economic opportunities, and that sort of thing.

15.   Population shifts have made Spanish as common as English.

16.   Religious organizations are also evolving as the population shifts.

17.   Scientists could detect population shifts among these boreal forest birds by studying tapes of their nocturnal flight calls recorded over several successive years, Evans suggested.

18.   Texas gets two more congressional seats because of population shifts.

19.   The economic trend fits with the population shift toward the South and the West of recent years reflected in the census.

20.   The small population shifts are important in determining new district lines.