How many regions had rainfall infiltration (km 3/year) of 9.3?
CREATE TABLE "key_characteristics_of_the_major_climati" (
  "region" text,
  "land_area_km_2" text,
  "rainfall_by_depth_mm_year" real,
  "rainfall_by_volume_km_3_year" text,
  "surface_run_off_km_3_year" text,
  "infiltration_km_3_year" text,
  "evapotranspiration_km_3_year" text
);
SELECT COUNT("rainfall_by_depth_mm_year") FROM "key_characteristics_of_the_major_climati" WHERE "infiltration_km_3_year"='9.3';