**EXHIBIT 12**

 

**COMPUTATION OF RATIOS**

**(UNAUDITED)**

 

Our consolidated ratios of earnings to fixed charges and earnings to combined fixed charges and preference dividends for each of the fiscal years ended December 31, 2005, 2004, 2003, 2002 and 2001 are as follows:

 

 

|                                                                                               |   | **Year Ended December 31,** |          |
|----------------------------------------------------------------------------------------------------|--------|-----------------------------|---------------|
| ($ in thousands)                                                                                   |   | **2006**                    |          | **2005** |   | **2004** |   | **2003** |   | **2002** |   |
| Net income from continuing operations                                                              |   | $                           | 607,292       |   | $ | 637,963 |   | $ | 668,871 |   | $ | 460,489 |   | $ | 389,272 |   |
| Minority interest of partially-owned entities                                                      |   |                        | (20,173       | ) |   | 3,808 |   |   | 109 |   |   | 1,089 |   |   | 3,534 |   |
| Equity in income of partially-owned entities in excess of distributions                            |   |                        | —        |   |   | — |   |   | (26,624 | ) |   | — |   |   | — |   |
| Fixed charges and preferred unit distributions                                                     |   |                        | 810,122       |   |   | 565,320 |   |   | 421,568 |   |   | 423,576 |   |   | 437,530 |   |
| Capitalized interest                                                                               |   |                        | (26,195       | ) |   | (15,582 | ) |   | (8,718 | ) |   | (5,407 | ) |   | (6,677 | ) |
|                                                                                               |   |                        |          |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Earnings - Numerator**                                                                           |   | **$**                       | **1,371,046** |   | **$** | **1,191,509** |   | **$** | **1,055,206** |   | **$** | **879,747** |   | **$** | **823,659** |   |
|                                                                                               |   |                        |          |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Interest and debt expense, including the Company’s pro-rata share of partially-owned entities |   | $                           | 692,496       |   | $ | 415,826 |   | $ | 313,289 |   | $ | 296,059 |   | $ | 305,920 |   |
| Capitalized interest                                                                               |   |                        | 26,195        |   |   | 15,582 |   |   | 8,718 |   |   | 5,407 |   |   | 6,677 |   |
| 1/3 of rental expense – interest factor                                                       |   |                        | 9,490         |   |   | 7,382 |   |   | 5,491 |   |   | 5,491 |   |   | 5,719 |   |
| **Fixed charges - Denominator**                                                                    |   |                        | **728,181**   |   |   | **438,790** |   |   | **327,498** |   |   | **306,957** |   |   | **318,316** |   |
| Preferred unit distributions                                                                       |   |                        | 81,941        |   |   | 126,530 |   |   | 94,070 |   |   | 116,619 |   |   | 119,214 |   |
| **Combined fixed charges and preferred unit distributions - Denominator**                          |   | **$**                       | **810,122**   |   | **$** | **565,320** |   | **$** | **421,568** |   | **$** | **423,576** |   | **$** | **437,530** |   |
|                                                                                               |   |                        |          |   |   |   |   |   |   |   |   |   |   |   |   |   |
| **Ratio of earnings to fixed charges**                                                             |   |                        | **1.88**      |   |   | **2.72** |   |   | **3.22** |   |   | **2.87** |   |   | **2.59** |   |
| **Ratio of earnings to combined fixed charges and preference dividends**                           |   |                        | **1.69**      |   |   | **2.11** |   |   | **2.50** |   |   | **2.08** |   |   | **1.88** |   |

 

Earnings equals (i) income from continuing operations before income taxes plus, (ii) minority interest in the Operating Partnership not included in fixed charges and (iii) fixed charges, minus (iv) equity in income of partially-owned entities in excess of distributions and (v) capitalized interest. Fixed charges equals (i) interest debt expense, plus (ii) the Company’s pro-rata share of interest expense of partially-owned entities, (iii) capitalized interest and (iv) the portion of operating lease rental expense that is representative of the interest factor, which is one-third of operating lease rentals. Combined fixed charges and preference dividends equals fixed charges plus preferred unit distributions of the Operating Partnership and  preferred share dividends.