Luke has a fondness for using about as a qualifier of numbers (see 1.15; 2.41; 10.3). It is quite possible that in each case Luke intends for the reader to understand the exact number and that he uses about merely as a stylistic device.

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on The Acts of the Apostles. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .