CREATE TABLE table_57608 ("Country" TEXT, "Abbreviation" TEXT, "Assets US$Billion" TEXT, "Inception" TEXT, "Origin" TEXT)

What's the inception for the country with 25.5 billion USD in assets and an abbreviation of psf?
SELECT "Inception" FROM table_57608 WHERE "Assets US$Billion" = '25.5' AND "Abbreviation" = 'psf'
SELECT "Inception" FROM "table_57608" WHERE "Abbreviation" = 'psf' AND "Assets US$Billion" = '25.5'