CREATE TABLE table_name_84 (pop_area__1_km²_ INTEGER, no_p VARCHAR(255), name VARCHAR(255))
Which Pop/Area (1/km²) has a No P. larger than 1, and a Name of albergaria-a-velha?
    
SQL: SELECT AVG(pop_area__1_km²_) FROM table_name_84 WHERE no_p > 1 AND name = "albergaria-a-velha"