Table schema:
CREATE TABLE table_name_98 (land_area__km²_ INTEGER, country VARCHAR, population_density__pop_per_km²_ VARCHAR)

Question: What is the land area of Switzerland with a population density fewer than 188 km²?
SQL: SELECT AVG(land_area__km²_) FROM table_name_98 WHERE country = "switzerland" AND population_density__pop_per_km²_ < 188