### Database Schema:
CREATE TABLE PaperAuthor (
	PaperId	INTEGER	NULL,
	AuthorId	INTEGER	NULL,
	Name	TEXT	NULL,
	Affiliation	TEXT	NULL,
	foreign key (AuthorId) references Author (Id),
	foreign key (PaperId) references Paper (Id)
);

CREATE TABLE Author (
	Id	INTEGER	NULL	PRIMARY KEY,
	Name	TEXT	NULL,
	Affiliation	TEXT	NULL
);

CREATE TABLE Paper (
	Id	INTEGER	NULL	PRIMARY KEY,
	Title	TEXT	NULL,
	Year	INTEGER	NULL,
	ConferenceId	INTEGER	NULL,
	JournalId	INTEGER	NULL,
	Keyword	TEXT	NULL,
	foreign key (JournalId) references Journal (Id),
	foreign key (ConferenceId) references Conference (Id)
);

CREATE TABLE Journal (
	Id	INTEGER	NULL	PRIMARY KEY,
	ShortName	TEXT	NULL,
	FullName	TEXT	NULL,
	HomePage	TEXT	NULL
);

CREATE TABLE Conference (
	Id	INTEGER	NULL	PRIMARY KEY,
	ShortName	TEXT	NULL,
	FullName	TEXT	NULL,
	HomePage	TEXT	NULL
);

### User's Query:
In papers with journal IDs from 200 to 300 and with its short name starts with A, what is the percentage of papers with conference ID of 0?

### Extra Knowledge:
journal ID of 200 to 300 refers to JournalId BETWEEN 200 AND 300; short name starts with A refers to ShortName LIKE 'A%'; Percentage = Divide (Count(ConferenceId = 0), Count(ConferenceId)) * 100
SELECT CAST(SUM(CASE WHEN T1.ConferenceId = 0 THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T1.ConferenceId) FROM Paper AS T1 INNER JOIN Journal AS T2 ON T1.JournalId = T2.Id WHERE T1.JournalId BETWEEN 200 AND 300 AND T2.ShortName LIKE 'A%'