hi andy-

i saw your post and thought about it for a while. what it comes down to is that it is really just a matter of doing some math.

i made a test which you can see here:

http://www.demetri-media.com/FlashTalker/pollingStation.swf
i attached the fla if you want to explore it. i didn't bother to try to 'optimize' it in any way.

you first need some variables to keep track of different numbers - one for the total number of people checked in, then one for each of the total number of each individual country.

then, each time a country button is chosen, the total number of attendees is advanced, the total number from that counry is advanced, and the %s are all calculated based on these updated numbers.

making the graph change is a matter of choice - there are numerous ways to do this - using a mask or not, using tweens or not. i just chose to increment the height of the bar +1 each click. of course there are limits that should be set to do this for real.

the placement of the ' % text ' can be done based on where the top of the bar is. i copped out and hard coded their initial positions. then their positions likewise get incremented by the same value as the bar ( which in my case was 1 )

my example only considered 2 of the countries, and did not consider the changing of their alphas. that can likewise be done by additional math.

if you have specific questions about my logic or code, feel free to ask

1779_pollingstation.fla.zip