The lowest number of strands usually seen is 7 ... one in the middle 
and 6 surrounding it. 
The next level up is 19, which is another layer of 12 strands on top 
of the 7. 
After that the number varies, but 37 and 49 are common, then in 
the 70 to 100 range (the number is no longer exact). Even larger 
numbers than that are typically found in very large cables.