1.   In other words, the random loss of certain lines of descent will mean that the average number of defects gradually increases.

2.   The average number of children per family was two and their average age was three.

3.   The average number of mites found in a case of scabies is about ten.

4.   The average number of quarrels per hour was three to four, although this was probably an underestimation.

5.   The rail system has triple the average number of accidents.

6.   This figure is less than the average number of new company registrations every month.

7.   What was the average monthly number of violations of Delta airspace by Gamma military airplanes?

8.   The average number of students in each class is creeping up from three to four.

9.   Figures for productivity based on the average number of publications per researcher per year within universities were derived from the database.