A chocolate bar manufacturer has been monitoring and trying to improve its productivity. The plant runs one $10-$hour shift per day in a $5-$day workweek. $15$ employees work in the plant. In Week $1,1250$ units were produced. Management made some changes in the next two weeks, including hiring $2$ more employees. In Week $4,1,501$ units were produced. What percent improvement in labor productivity $($units$/$hr$)$ did the plant achieve from Week $1$ to Week $4?($DO NOT ROUND UNTIL END$)$

Enter your response without the $\%$ sign & rounded to $1$ decimal place.