Exhibit 99.31 MBNA MASTER CREDIT CARD TRUST II SERIES 1997-N KEY PERFORMANCE FACTORS March 31, 1999 Expected B Maturity 11/15/00 Blended Coupon 5.1075% Excess Protection Level 3 Month Average 6.12% March, 1999 6.77% February, 1999 6.09% January, 1999 5.49% Cash Yield 19.20% Investor Charge Offs 5.12% Base Rate 7.30% Over 35 Day Delinquency 4.94% Seller's Interest 6.34% Total Payment Rate 14.77% Total Principal Balance $40,628,355,078.94 Investor Participation Amount $900,000,000.00 Seller Participation Amount $2,576,435,560.45