Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_19948664_1 ( countries_sampled INTEGER, index__year_ VARCHAR )

### Question ###
How many countries were sampled for the Prosperity Index (2008)?

### Accurate SQL ###

SELECT MAX(countries_sampled) FROM table_19948664_1 WHERE index__year_ = "Prosperity Index (2008)"