The Big Black Bird Company $($BBBC$)$ has a large order for special plastic$-$lined military uniforms to be used in an urgent military operation. Working the normal two shifts of $40$ hours each per week, the BBBC production process usually produces $2,400$ uniforms per week at a standard cost of $$120$ each. $68$ employees work the first shift and $32$ the second. The contract price is $$200$ peruniform. Because of the urgent need, BBBC is authorized to use around$-$the$-$clock production six days per week. When each of the two shifts works $72$ hours per week, production increases to $4,200$ uniforms per week but at a cost of $$144$ each.

a$.$ The multifactor productivity level decreased for two shifts working $72$ hours when compared to the level of the normal two shifts.

The multifactor productivity ratio based on the normal two shifts changed by $\%$ as compared to two shifts working $72$ hours per week. $($Enter your response rounded to two decimal places.$)$