### Database Schema:
CREATE TABLE location (
	id_restaurant	INTEGER	NOT NULL	PRIMARY KEY,
	street_num	INTEGER	NULL,
	street_name	TEXT	NULL,
	city	TEXT	NULL,
	foreign key (city) references geographic (city),
	foreign key (id_restaurant) references generalinfo (id_restaurant)
);

CREATE TABLE geographic (
	city	TEXT	NOT NULL	PRIMARY KEY,
	county	TEXT	NULL,
	region	TEXT	NULL
);

CREATE TABLE generalinfo (
	id_restaurant	INTEGER	NOT NULL	PRIMARY KEY,
	label	TEXT	NULL,
	food_type	TEXT	NULL,
	city	TEXT	NULL,
	review	REAL	NULL,
	foreign key (city) references geographic (city)
);

### User's Query:
Among the restaurants located on the street number ranges from 1000 to 2000, what is the percentage of Afghani restaurants are there?

### Extra Knowledge:
street number ranges from 1000 to 2000 refers to 1000 < = street_num < = 2000; Afghani restaurant refers to food_type = 'afghani'; percentage = divide(count(id_restaurant where food_type = 'afghani'), count(id_restaurant)) * 100%
SELECT CAST(SUM(IIF(T2.food_type = 'afghani', 1, 0)) AS REAL) * 100 / COUNT(T1.id_restaurant) FROM location AS T1 INNER JOIN generalinfo AS T2 ON T1.id_restaurant = T2.id_restaurant WHERE 1000 <= T1.street_num <= 2000