Exhibit 99.31 MBNA MASTER CREDIT CARD TRUST II SERIES 1997-N KEY PERFORMANCE FACTORS August 31, 1999 Expected B Maturity 11/15/00 Blended Coupon 5.5499% Excess Protection Level 3 Month Average 5.82% August, 1999 5.85% July, 1999 6.33% June, 1999 5.28% Cash Yield 18.20% Investor Charge Offs 4.78% Base Rate 7.58% Over 30 Day Delinquency 4.81% Seller's Interest 7.19% Total Payment Rate 14.37% Total Principal Balance $46,158,397,644.87 Investor Participation Amount $900,000,000.00 Seller Participation Amount $3,316,578,126.38