#Creates a empty dataframe
dataset0514maxrec = pd.DataFrame(columns=dataset0514max.columns.values)
dataset0514maxrec.index.name = 'Date'

#Gets the unique values, find the groups, recover the max value and append it
for i in dataset0514max.index.unique():
    tempDF1 = dataset0514max.loc[dataset0514max.index.isin([i])]
    tempDF2 = tempDF1[tempDF1['Data_Value'] == tempDF1['Data_Value'].max()]
    dataset0514maxrec = dataset0514maxrec.append(tempDF2.head(1))

print(dataset0514maxrec)