PS_data = data[4:11,1]
PNS_data = data[4:11,2]
PRS_data = data[4:11,3]
PRNS_data = data[4:11,4]
def change(a,b):
answer = np.diff(PS_data) / PS_data[0] * 100
return answer
print(change(PS_data,0))
This is the code but it only gives me the correct answer for the first percentage change. If i change the '0' to '1', it will show me the correct answer for only the 2nd answer.