Return the codes of countries for which Spanish is the predominantly spoken language.
SELECT CountryCode ,  max(Percentage) FROM countrylanguage WHERE LANGUAGE  =  "Spanish" GROUP BY CountryCode
SELECT CountryCode ,  max(Percentage) FROM countrylanguage WHERE LANGUAGE  =  "Spanish" GROUP BY CountryCode
[{'CountryCode': 'ABW', 'max(Percentage)': 7.4}, {'CountryCode': 'AND', 'max(Percentage)': 44.6}, {'CountryCode': 'ARG', 'max(Percentage)': 96.8}, {'CountryCode': 'BLZ', 'max(Percentage)': 31.6}, {'CountryCode': 'BOL', 'max(Percentage)': 87.7}, {'CountryCode': 'CAN', 'max(Percentage)': 0.7}, {'CountryCode': 'CHL', 'max(Percentage)': 89.7}, {'CountryCode': 'COL', 'max(Percentage)': 99.0}, {'CountryCode': 'CRI', 'max(Percentage)': 97.5}, {'CountryCode': 'CUB', 'max(Percentage)': 100.0}, {'CountryCode': 'DOM', 'max(Percentage)': 98.0}, {'CountryCode': 'ECU', 'max(Percentage)': 93.0}, {'CountryCode': 'ESP', 'max(Percentage)': 74.4}, {'CountryCode': 'FRA', 'max(Percentage)': 0.4}, {'CountryCode': 'GTM', 'max(Percentage)': 64.7}, {'CountryCode': 'HND', 'max(Percentage)': 97.2}, {'CountryCode': 'MEX', 'max(Percentage)': 92.1}, {'CountryCode': 'NIC', 'max(Percentage)': 97.6}, {'CountryCode': 'PAN', 'max(Percentage)': 76.8}, {'CountryCode': 'PER', 'max(Percentage)': 79.8}, {'CountryCode': 'PRI', 'max(Percentage)': 51.3}, {'CountryCode': 'PRY', 'max(Percentage)': 55.1}, {'CountryCode': 'SLV', 'max(Percentage)': 100.0}, {'CountryCode': 'SWE', 'max(Percentage)': 0.6}, {'CountryCode': 'URY', 'max(Percentage)': 95.7}, {'CountryCode': 'USA', 'max(Percentage)': 7.5}, {'CountryCode': 'VEN', 'max(Percentage)': 96.9}, {'CountryCode': 'VIR', 'max(Percentage)': 13.3}]