### Database Schema:
CREATE TABLE movie (
	MovieID	INTEGER	NULL	PRIMARY KEY,
	Title	TEXT	NULL,
	`MPAA Rating`	TEXT	NULL,
	Budget	INTEGER	NULL,
	Gross	INTEGER	NULL,
	`Release Date`	TEXT	NULL,
	Genre	TEXT	NULL,
	Runtime	INTEGER	NULL,
	Rating	REAL	NULL,
	`Rating Count`	INTEGER	NULL,
	Summary	TEXT	NULL
);

CREATE TABLE characters (
	MovieID	INTEGER	NULL	PRIMARY KEY,
	ActorID	INTEGER	NULL	PRIMARY KEY,
	`Character Name`	TEXT	NULL,
	creditOrder	INTEGER	NULL,
	pay	TEXT	NULL,
	screentime	TEXT	NULL,
	foreign key (MovieID) references movie (MovieID),
	foreign key (ActorID) references actor (ActorID)
);

CREATE TABLE actor (
	ActorID	INTEGER	NULL	PRIMARY KEY,
	Name	TEXT	NULL,
	`Date of Birth`	DATE	NULL,
	`Birth City`	TEXT	NULL,
	`Birth Country`	TEXT	NULL,
	`Height (Inches)`	INTEGER	NULL,
	Biography	TEXT	NULL,
	Gender	TEXT	NULL,
	Ethnicity	TEXT	NULL,
	NetWorth	TEXT	NULL
);

### User's Query:
What is the percentage of the USA actors that showed up in the credit list of movie "Mrs. Doubtfire"?

### Extra Knowledge:
USA actors refers to Birth Country = 'USA'; movie "Mrs. Doubtfire" refers to Title = 'Mrs. Doubtfire'; percentage = divide(count(ActorID where Birth Country = 'USA'), count(ActorID)) * 100%
SELECT CAST(SUM(CASE WHEN T3.`Birth Country` = 'USA' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T3.`Birth Country`) FROM movie AS T1 INNER JOIN characters AS T2 ON T1.MovieID = T2.MovieID INNER JOIN actor AS T3 ON T3.ActorID = T2.ActorID WHERE T1.Title = 'Mrs. Doubtfire'