A cleaning company uses $10lbs$ each of chemicals A$,$ B and C for each house it cleans. After some quality complaints, the company has decided to increase its use of chemical A by an additional $10$ lbs for each house. By what $\%$ has productivity $($houses per pound of chemical$)$ fallen?

$25\%$

$15\%$

$0\%$

$10\%$

$33\%$