which way to read this timing tab

[moparjohnny]

i see 10 but what if you needed 15,which direction would the higher numbers go,how much does each little mark count for in degrees. would 15 be on left or right of the before. thanks

 

[BBishere2]

Looking at the picture 15 BTDC would be to the right of 'BEFORE'

 

[Shorthorse]

5 degrees per mark.