Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| # | Date | Opponent | Score | Win | Loss | Save | Attendance | Record |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 136 | September 1 | @ Cubs | 4 - 3 | Marquis (11-8) | Patton (0-2) | Dempster (24) | 40,606 | 61-75 |
| 137 | September 2 | @ Cubs | 6 - 5 | Marmol (5-1) | Qualls (6-4) | Dempster (25) | 41,415 | 61-76 |
| 138 | September 3 | @ Brewers | 9 - 7 | Borkowski (4-3) | Aquino (0-1) | Qualls (4) | 31,226 | 62-76 |
| 139 | September 4 | @ Brewers | 5 - 3 | Villanueva (7-3) | Backe (0-1) | Cordero (40) | 25,854 | 62-77 |
| 140 | September 5 | @ Brewers | 14 - 2 | Gallardo (7-4) | Albers (4-7) |  | 28,988 | 62-78 |
| 141 | September 7 | @ Mets | 11 - 3 | Pelfrey (2-7) | Rodríguez (8-13) |  | 51,113 | 62-79 |
| 142 | September 8 | @ Mets | 3 - 1 | Glavine (13-6) | Williams (8-14) | Wagner (31) | 53,061 | 62-80 |
| 143 | September 9 | @ Mets | 4 - 1 | Martínez (2-0) | Oswalt (14-7) | Wagner (32) | 51,847 | 62-81 |
| 144 | September 11 | Cubs | 5 - 4 (11) | Lidge (4-2) | Dempster (2-6) |  | 33,493 | 63-81 |
| 145 | September 12 | Cubs | 3 - 2 | Hill (9-8) | Albers (4-8) | Dempster (26) | 33,115 | 63-82 |
| 146 | September 13 | Cubs | 6 - 2 | Trachsel (7-10) | Williams (8-15) |  | 34,234 | 63-83 |
| 147 | September 14 | Pirates | 4 - 3 | Sánchez (1-0) | Qualls (6-5) | Capps (17) | 35,352 | 63-84 |
| 148 | September 15 | Pirates | 9 - 7 | Gutiérrez (1-1) | Morris (9-10) | Lidge (15) | 40,425 | 64-84 |
| 149 | September 16 | Pirates | 15 - 3 | Backe (1-1) | Maholm (10-15) |  | 35,715 | 65-84 |
| 150 | September 17 | Brewers | 6 - 0 | Gallardo (9-4) | Albers (4-9) |  | 32,578 | 65-85 |
| 151 | September 18 | Brewers | 9 - 1 | Vargas (11-4) | Paulino (0-1) |  | 32,866 | 65-86 |
| 152 | September 19 | Brewers | 5 - 4 (10) | Lidge (5-2) | Wise (3-2) |  | 36,981 | 66-86 |
| 153 | September 20 | @ Cardinals | 18 - 1 | Rodríguez (9-13) | Looper (12-11) |  | 42,171 | 67-86 |
| 154 | September 21 | @ Cardinals | 6 - 3 | Backe (2-1) | Piñeiro (6-5) | Lidge (16) | 43,677 | 68-86 |
| 155 | September 22 | @ Cardinals | 7 - 4 | Thompson (7-6) | Albers (4-10) | Isringhausen (30) | 46,237 | 68-87 |
| 156 | September 23 | @ Cardinals | 4 - 3 | Jiménez (3-0) | Lidge (5-3) |  | 46,169 | 68-88 |
| 157 | September 25 | @ Reds | 8 - 5 | Paulino (1-1) | Coutlangus (4-2) | Lidge (17) | 13,261 | 69-88 |
| 158 | September 26 | @ Reds | 7 - 6 | Sarfate (1-0) | Burton (4-2) | Qualls (5) | 13,138 | 70-88 |
| 159 | September 27 | @ Reds | 4 - 3 | Borkowski (5-3) | Majewski (0-4) | Lidge (18) | 13,626 | 71-88 |
| 160 | September 28 | Braves | 7 - 2 | Reyes (2-2) | Albers (4-11) |  | 43,011 | 71-89 |
| 161 | September 29 | Braves | 3 - 2 | Backe (3-1) | Bennett (2-1) | Lidge (19) | 43,624 | 72-89 |
| 162 | September 30 | Braves | 3 - 0 | Paulino (2-1) | Carlyle (8-7) | Borkowski (1) | 43,823 | 73-89 |
Question:
what was the difference in runs between the two teams on september 15?
Answer:
2