Question

Last year, sales at a book store increased from $5,000 to $10,000. This year, sales decreased to $5,000 from $10,000. What percentage did sales increase last year? What percentage did sales decrease this year?
Sales increased _____ last year, from $5,000 to $10,000. When sales dropped from $10,000 to $5,000 this year, sales decreased _____ .