Hello, try the following... I've seen int have this problem before...
double percentage = ((double)value / (double)max) * 100);
If your initial thought on reading this is 'that can't be it'... try this simple console test...
int val = 5;
int total = 100;
int pct = (val / total) * 100;
Console.WriteLine(pct);
pct always zero... make everything double and hey... dar it goes.