changing multiple velocities

Can anyone tell me how to increase the velocity of all the midi notes in a sixteen bar streach while keeping the same velocity ratio between the notes.  I don't want them all to have the exact same velocity value but preserve the original feel.  Hope I'm being clear.
 
Thanks in advance

Thanks bro.  I would have had my head in the manual for an hour to find that one.  Worked great.

And you can use the excellent Midi Velocity tool which provides a whole host of options for changing velocities