Need quick help for completing thesis in time

Under statistical analysis this was the revised statement from my professor i cant understand what the % of cases mean ? Is it the number of participants? there where many participants,but i selected only a group of participants from the data set. Can someone help ?

SPSS for windows (IBM, statistics 22) was used for data entry, data graphing and all statistical calculations. Data quality was insured by crosschecking original records with data entered into the SPSS file in X% of cases.

please and thank you