If I do 4 selects in order 1, 2, 3, 4, using UNION ALL, the results come back 1, 4, 3, 2. Why?

I can use ORDER BY to rearrange the order, but why is it in this seemingly "out of order" order by default?

Use this table:

CREATE TABLE "AACoupons" (
"AACouponID" INTEGER NOT NULL DEFAULT AUTOINCREMENT,
"CouponAmount" INTEGER NULL,
"AAItemID" INTEGER NULL,
PRIMARY KEY ( "AACouponID" ASC )
) ;

INSERT INTO "AACoupons" ("AACouponID","CouponAmount","AAItemID") VALUES(200,2,3);
INSERT INTO "AACoupons" ("AACouponID","CouponAmount","AAItemID") VALUES(201,4,3);
INSERT INTO "AACoupons" ("AACouponID","CouponAmount","AAItemID") VALUES(202,6,3); 
INSERT INTO "AACoupons" ("AACouponID","CouponAmount","AAItemID") VALUES(500,162,NULL);
INSERT INTO "AACoupons" ("AACouponID","CouponAmount","AAItemID") VALUES(501,NULL,NULL);
INSERT INTO "AACoupons" ("AACouponID","CouponAmount","AAItemID") VALUES(506,NULL,NULL);

Use this SELECT block:

select AACouponID as ID, 'ID1' as "Type" from aacoupons
where ID = 201
union all
select AACouponID as ID, 'ID2' as "Type" from aacoupons
where ID = 201
union all
select AACouponID as ID, 'ID3' as "Type" from aacoupons
where ID = 201
 union all
select AACouponID as ID, 'ID4' as "Type" from aacoupons
where ID = 201

Results:

ID,Type
201,'ID1'
201,'ID4'
201,'ID3'
201,'ID2'