Security Group 1 PSA Prepayment Assumption Rates Class TE Classes TG, TK and TL Distribution Date 0% 100% 275% 350% 550% 0% 100% 275% 350% 550% Initial Percent ..................    100 100 100 100 100 100 100 100 100 100 October 2008....................    100 100 100 100 100 100 100 92 92 92 October 2009....................    100 100 100 100 100 100 100 75 75 75 October 2010....................    100 100 100 100 0 100 100 53 53 27 October 2011....................    100 100 100 100 0 100 100 34 34 0 October 2012....................    100 100 100 100 0 100 100 19 19 0 October 2013....................    100 100 100 94 0 100 100 8 8 0 October 2014....................    100 100 100 71 0 100 100 0 0 0 October 2015....................    100 100 100 63 0 100 100 0 0 0 October 2016....................    100 100 100 63 0 100 92 0 0 0 October 2017....................    100 100 100 63 0 100 78 0 0 0 October 2018....................    100 100 100 63 0 100 59 0 0 0 October 2019....................    100 100 100 63 0 100 37 0 0 0 October 2020....................    100 100 100 63 0 100 12 0 0 0 October 2021....................    100 100 100 63 0 100 0 0 0 0 October 2022....................    100 100 100 63 0 100 0 0 0 0 October 2023....................    100 100 100 63 0 100 0 0 0 0 October 2024....................    100 100 100 56 0 100 0 0 0 0 October 2025....................    100 100 100 42 0 100 0 0 0 0 October 2026....................    100 100 84 31 0 100 0 0 0 0 October 2027....................    100 100 65 23 0 100 0 0 0 0 October 2028....................    100 100 51 17 0 100 0 0 0 0 October 2029....................    100 100 39 12 0 100 0 0 0 0 October 2030....................    100 100 29 9 0 100 0 0 0 0 October 2031....................    100 100 21 6 0 95 0 0 0 0 October 2032....................    100 100 15 4 0 30 0 0 0 0 October 2033....................    100 100 10 3 0 0 0 0 0 0 October 2034....................    100 100 7 2 0 0 0 0 0 0 October 2035....................    100 90 4 1 0 0 0 0 0 0 October 2036....................    100 40 1 0 0 0 0 0 0 0 October 2037.................... 0 0 0 0 0 0 0 0 0 0 Weighted Average Life (years)  ..................   29.8 28.8 21.8 14.9 2.7 24.7 11.3 3.3 3.3 2.5 Security Group 2 PSA Prepayment Assumption Rates Classes YC and YD Class Z Distribution Date 0% 100% 265% 400% 550% 0% 100% 265% 400% 550% Initial Percent ..................    100 100 100 100 100 100 100 100 100 100 October 2008.................... 99 99 81 67 44 106 106 65 0 0 October 2009.................... 99 99 56 16 0 113 113 23 0 0 October 2010.................... 98 98 34 0 0 120 120 0 0 0 October 2011.................... 97 97 15 0 0 127 127 0 0 0 October 2012.................... 96 96 3 0 0 135 135 0 0 0 October 2013.................... 95 95 0 0 0 143 143 0 0 0 October 2014.................... 94 94 0 0 0 152 152 0 0 0 October 2015.................... 93 93 0 0 0 161 161 0 0 0 October 2016.................... 92 92 0 0 0 171 171 0 0 0 October 2017.................... 91 91 0 0 0 182 182 0 0 0 October 2018.................... 90 90 0 0 0 193 193 0 0 0 October 2019.................... 88 88 0 0 0 205 205 0 0 0 October 2020.................... 87 83 0 0 0 218 218 0 0 0 October 2021.................... 85 75 0 0 0 231 231 0 0 0 October 2022.................... 84 66 0 0 0 245 245 0 0 0 October 2023.................... 82 57 0 0 0 261 261 0 0 0 October 2024.................... 80 48 0 0 0 277 277 0 0 0 October 2025.................... 78 38 0 0 0 294 294 0 0 0 October 2026.................... 76 29 0 0 0 312 312 0 0 0 October 2027.................... 74 19 0 0 0 331 331 0 0 0 October 2028.................... 72 9 0 0 0 351 351 0 0 0 October 2029.................... 70 0 0 0 0 373 371 0 0 0 October 2030.................... 67 0 0 0 0 396 309 0 0 0 October 2031.................... 64 0 0 0 0 421 248 0 0 0 October 2032.................... 53 0 0 0 0 446 191 0 0 0 October 2033.................... 25 0 0 0 0 474 137 0 0 0 October 2034.................... 0 0 0 0 0 484 90 0 0 0 October 2035.................... 0 0 0 0 0 269 47 0 0 0 October 2036.................... 0 0 0 0 0 77 13 0 0 0 October 2037.................... 0 0 0 0 0 0 0 0 0 0 Weighted Average Life (years)  ..................   21.8 16.1 2.4 1.3 0.9 28.1 25.3 1.4 0.3 0.1 S-21