Exhibit 99.31 MBNA MASTER CREDIT CARD TRUST II SERIES 1997-N KEY PERFORMANCE FACTORS June 30, 1999 Expected B Maturity 11/15/00 Blended Coupon 5.1093% Excess Protection Level 3 Month Average 6.04% June, 1999 5.28% May, 1999 7.61% April, 1999 5.21% Cash Yield 17.46% Investor Charge Offs 5.06% Base Rate 7.11% Over 30 Day Delinquency 4.82% Seller's Interest 11.01% Total Payment Rate 13.71% Total Principal Balance $44,380,968,357.42 Investor Participation Amount $900,000,000.00 Seller Participation Amount $4,888,448,838.93