[Python] using a pandas data frame and it is returning NaN, but when I print the value it is...

I am using pandas for the first time, and in the data frame there is a piece of data that is a percentage as a string but when put into a dataframe and printed it shows up as NaN. So to test it i just used a print statement and it returns the value fine. Thank you!

def makeSheet():
data = [schoolName, location, aceptanceRate, tuition, roomAndBoard, debtAtGrad, studentToTeacher, satReq, totalUndergrad]
dataDictonary = {"School Name": schoolName, "Location": location, "Aceptance Rate": aceptanceRate, "Tuition": tuition, "Room & Board": roomAndBoard, "Estimated Debt at Grad": debtAtGrad, "Student:Teacher": studentToTeacher,
"SAT Req": satReq, "Total Number of Undergrads": totalUndergrad}
df = pd.DataFrame(dataDictonary, columns=headers, index=[0])
print(df)
print(aceptanceRate)


the pandas data table returned: pandas data table

The print statement returned: 31%

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