Thanks Fabio you reply,
i am not getting percentage correct
with out sum result correct but when i use these codes not get corret.
Can you describe me more

TRANSFORM((sum(tobt)/sum(tmax))*100,"##.##") AS PERCENTAGE,;
  TRANSFORM(ROUND((SUM(tobt)/SUM(tmax))*100,2),"##.##") AS PERCENTAGEu;