CREATE TABLE table_12242 ("County" TEXT, "Per capita income" TEXT, "Median household income" TEXT, "Median family income" TEXT, "Population" FLOAT, "Number of households" FLOAT)

How many households have a Median household income of $43,889?
SELECT AVG("Number of households") FROM table_12242 WHERE "Median household income" = '$43,889'
SELECT AVG("Number of households") FROM "table_12242" WHERE "Median household income" = '$43,889'