how to measure the productivity difference of two nurses

I have this data with 60 observations for continues three days hours, in which two nurses work in irregular shifts to cover this whole period:

hours   Productivity    Nurse 
1                 50%       A
2                 40%       A
3                 20%       B
4                 10%       A
5                 60%       B
6                15%        B
7                15%        B
.   .   
.   .   
.   .   
60                5%         A

I have been asked to build a time series model for the Productivity and decide whether there a strong Productivity difference between nurse A and nurse B. what is the right statistical approach to handle this question? thanks for the kind help in advance