For each citizenship, what is the maximum net worth?
SELECT Citizenship ,  max(Net_Worth_Millions) FROM singer GROUP BY Citizenship
SELECT Citizenship ,  max(Net_Worth_Millions) FROM singer GROUP BY Citizenship
[{'Citizenship': 'Australia', 'max(Net_Worth_Millions)': 17.0}, {'Citizenship': 'Chile', 'max(Net_Worth_Millions)': 17.4}, {'Citizenship': 'France', 'max(Net_Worth_Millions)': 30.0}, {'Citizenship': 'Germany', 'max(Net_Worth_Millions)': 14.3}, {'Citizenship': 'United States', 'max(Net_Worth_Millions)': 28.8}]