Exhibit 12

Ratio of Earnings to Combined Fixed Charges and Preference Dividends
<TABLE>
<CAPTION>
                                                                       December 31,
                                               -------------------------------------------------------------
(DOLLARS IN THOUSANDS)                            2007         2006         2005         2004         2003
                                               ---------    ---------    ---------    ---------    ---------
<S>                                            <C>          <C>          <C>          <C>          <C>
Interest expense                               $ 245,557    $ 145,779    $  83,420    $  52,327    $  23,919
Amortized capitalized costs related to
  indebtedness                                     3,484        5,431        2,642        3,310        2,245

Preference security dividend requirements of
  consolidated subsidiaries                       25,123       25,123       25,123       22,840       18,897
                                               ---------    ---------    ---------    ---------    ---------

Total fixed charges                            $ 274,164    $ 176,333    $ 111,185    $  78,477    $  45,061
                                               =========    =========    =========    =========    =========

Net income before minority interests           $(478,625)   $(337,497)   $(295,673)   $(143,462)   $  64,498
Add:  Total fixed charges                        274,164      176,333      111,185       78,477       45,061
Less:  Preference security dividend
  requirements of consolidated subsidiaries      (25,123)     (25,123)     (25,123)     (22,840)     (18,897)
                                               ---------    ---------    ---------    ---------    ---------

Earnings                                       $(229,584)   $(186,287)   $(209,611)   $ (87,825)   $  90,662
                                               =========    =========    =========    =========    =========

Ratio of Earnings to Combined Fixed Charges
  and Preference Dividends                      See Note     See Note     See Note     See Note        2.0:1

Shortfall                                      $ 503,748    $ 362,620    $ 320,796    $ 166,302    $      --
                                               =========    =========    =========    =========    =========
</TABLE>

For the  purposes  of  computing  the ratio of  earnings  to fixed  charges  and
preference  dividends,  earnings were  calculated  using income before  minority
interests  adding back total fixed  charges less  preference  security  dividend
requirements  of  consolidated  subsidiaries.  Fixed charges consist of interest
expense,  recurring  fees and  amortization  of  capitalized  costs  related  to
indebtedness  and preference  security  dividend  requirements  of  consolidated
subsidiaries.

Earnings were insufficient to cover fixed charges (both as defined in Regulation
S-K)  in  periods  shown  above  due  to  the  inclusion  of  fixed  charges  of
partnerships that we consolidate in our financial  statements in accordance with
accounting  pronouncements  such as FASB  Interpretation  No.  46(R).  The fixed
charges  of  those  partnerships  are not  paid by us and  the  related  debt is
non-recourse to us. Likewise,  the net losses incurred by those partnerships are
allocated to their  limited  partners that own a majority (or all) of the equity
of the partnerships.

A  reconciliation  of the  amounts  as defined  in  Regulation  S-K to the fixed
charges  actually  paid by us and our earnings  that are allocated to our equity
holders results in a positive ratio for all periods and is as follows:
<TABLE>
<CAPTION>
                                                                    Year ended December 31,
                                                -------------------------------------------------------------
(DOLLARS IN THOUSANDS)                             2007         2006         2005         2004         2003
                                                ---------    ---------    ---------    ---------    ---------
<S>                                             <C>          <C>          <C>          <C>          <C>
Total fixed charges as defined                  $ 274,164    $ 176,333    $ 111,185    $  78,477    $  45,061
Less: interest of consolidated partnerships
  on debt that is non-recourse to the Company    (100,321)     (47,926)     (26,322)     (21,395)          --
                                                ---------    ---------    ---------    ---------    ---------
Total fixed charges as adjusted                 $ 173,843    $ 128,407    $  84,863    $  57,082    $  45,061
                                                =========    =========    =========    =========    =========

Earnings as defined                             $(229,584)   $(186,287)   $(209,611)   $ (87,825)   $  90,662

Allocation of losses incurred by consolidated
  partnerships to the limited partners of
  those partnerships                              398,893      401,377      349,531      219,950           --
                                                ---------    ---------    ---------    ---------    ---------
Earnings as adjusted                            $ 169,309    $ 215,090    $ 139,920    $ 132,125    $  90,662
                                                =========    =========    =========    =========    =========

Ratio of Earnings to Combined Fixed Charges
  and Preference Dividends excluding
  consolidated partnerships                           1.0          1.7          1.6          2.3          2.0
                                                =========    =========    =========    =========    =========


Shortfall                                       $   4,534    $      --    $      --    $      --    $      --
                                                =========    =========    =========    =========    =========
</TABLE>