We estimate that our net proceeds from the sale of the shares of common stock in this offering will be approximately $492.6 million, after deducting underwriting discounts and commissions and estimated offering expenses that we must pay. If the underwriters’ option to purchase additional shares in this offering is exercised in full, we estimate that our net proceeds in this offering will be approximately $566.5 million, after deducting underwriting discounts and commissions and estimated offering expenses that we must pay. The estimated net proceeds are based on the assumed public offering price of $238.17 per share, which was the last reported sale price of our common stock on August 12, 2015. Each $1.00 increase or decrease in the assumed public offering price of $238.17 per share would increase or decrease, as applicable, our net proceeds from this offering by approximately $2.1 million, assuming that the number of shares offered by us, as set forth on the cover page of this prospectus supplement, remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us. Each 1.0 million increase or decrease in the number of shares offered by us, as set forth on the cover page of this prospectus supplement, would increase or decrease, as applicable, our net proceeds from this offering by approximately $234.7 million, assuming that the assumed public offering price of $238.17 per share remains the same and after deducting the estimated underwriting discounts and commissions and estimated offering expenses payable by us.