Percentages of Original Class Principal (or Class Notional) Balances and Weighted Average Lives Security Group 1 PSA Prepayment Assumption Rates Classes EA, FA, SA, SB, SC, SD, SE, UA and UB Class ZA Distribution Date 0% 100% 225% 350% 500% 0% 100% 225% 350% 500% Initial Percent ..................    100 100 100 100 100 100 100 100 100 100 May 2005  .......................... 98 96 94 94 94 106 106 93 58 17 May 2006  .......................... 96 89 83 82 72 113 113 81 0 0 May 2007  .......................... 94 81 71 64 50 120 120 68 0 0 May 2008  .......................... 92 74 60 50 34 127 127 60 0 0 May 2009  .......................... 90 67 51 39 24 135 135 55 0 0 May 2010  .......................... 87 60 43 30 16 143 143 52 0 0 May 2011  .......................... 85 53 36 23 11 152 152 50 0 0 May 2012  .......................... 82 47 30 18 8 161 161 49 0 0 May 2013  .......................... 79 41 25 14 5 171 171 47 0 0 May 2014  .......................... 76 36 20 11 4 182 182 44 0 0 May 2015  .......................... 73 30 17 8 2 193 193 41 0 0 May 2016  .......................... 69 25 14 6 2 205 205 37 0 0 May 2017  .......................... 65 20 11 5 1 218 218 34 0 0 May 2018  .......................... 61 15 9 4 1 231 231 30 0 0 May 2019  .......................... 57 10 8 3 1 245 245 27 0 0 May 2020  .......................... 52 6 6 2 0 261 255 24 0 0 May 2021  .......................... 48 5 5 2 0 277 234 20 0 0 May 2022  .......................... 42 4 4 1 0 294 213 18 0 0 May 2023  .......................... 37 3 3 1 0 312 192 15 0 0 May 2024  .......................... 31 3 3 1 0 331 171 13 0 0 May 2025  .......................... 25 2 2 0 0 351 150 11 0 0 May 2026  .......................... 18 2 2 0 0 373 130 9 0 0 May 2027  .......................... 11 1 1 0 0 396 110 7 0 0 May 2028  .......................... 3 1 1 0 0 421 91 5 0 0 May 2029  .......................... 1 1 1 0 0 384 73 4 0 0 May 2030  .......................... 0 0 0 0 0 318 55 3 0 0 May 2031  .......................... 0 0 0 0 0 247 38 2 0 0 May 2032  .......................... 0 0 0 0 0 170 22 1 0 0 May 2033  .......................... 0 0 0 0 0 88 6 0 0 0 May 2034  .......................... 0 0 0 0 0 0 0 0 0 0 Weighted Average Life (years)  ..................   15.2 8.2 6.5 5.1 3.7 27.4 22.2 9.5 1.1 0.7 Security Groups 1 and 5 PSA Prepayment Assumption Rates Class ZD Distribution Date 0% 100% 225% 350% 500% Initial Percent ..................    100 100 100 100 100 May 2005  ..........................    106 106 93 58 17 May 2006  ..........................    113 113 81 0 0 May 2007  ..........................    120 120 68 0 0 May 2008  ..........................    127 127 60 0 0 May 2009  ..........................    135 135 55 0 0 May 2010  ..........................    143 143 52 0 0 May 2011  ..........................    152 152 50 0 0 May 2012  ..........................    161 161 49 0 0 May 2013  ..........................    171 171 47 0 0 May 2014  ..........................    182 182 44 0 0 May 2015  ..........................    193 193 41 0 0 May 2016  ..........................    205 205 37 0 0 May 2017  ..........................    218 218 34 0 0 May 2018  ..........................    231 231 30 0 0 May 2019  ..........................    245 245 27 0 0 May 2020  ..........................    261 255 24 0 0 May 2021  ..........................    277 234 20 0 0 May 2022  ..........................    294 213 18 0 0 May 2023  ..........................    312 192 15 0 0 May 2024  ..........................    331 171 13 0 0 May 2025  ..........................    351 150 11 0 0 May 2026  ..........................    373 130 9 0 0 May 2027  ..........................    396 110 7 0 0 May 2028  ..........................    421 91 5 0 0 May 2029  ..........................    384 73 4 0 0 May 2030  ..........................    318 55 3 0 0 May 2031  ..........................    247 38 2 0 0 May 2032  ..........................    170 22 1 0 0 May 2033  .......................... 88 6 0 0 0 May 2034  .......................... 0 0 0 0 0 Weighted Average Life (years)  ..................   27.4 22.2 9.5 1.1 0.7 S-24