高橋保夫 (1997), Swam, M. Practical English Usage, OUP.

高橋、Swan p. 65

the number ofの後では、本来あるべきtheが落ちる。
(1) The number of unemployed is rising steadily. (the +形容詞のthe)
(2) The numbers indicate the number of nearest neighbors. (BC G20-0630) (最上級のthe)
(3) Are your expenses in this area commensurate with the number of employees who benefit from your program?

(BC E30-0550) (後置修飾から期待されるthe)