Sleep Number Corp. shares dropped more than 10% in after-hours trading Wednesday after the mattress maker reported quarterly earnings. Sleep Number reported profit of $25.4 million, or 80 cents a share, on revenue of $426.5 million, up from earnings of 52 cents a share on sales of $388.6 million a year ago. Sales came up slightly short of average analyst expectations, which called for earnings of 73 cents a share on sales of $428 million. Shares closed down 1.6% Wednesday, after a sharp decline in the afternoon. The stock has gained 30% in the past year, as the S&P 500 index has increased 7.4%.