what was the average beginning and ending balance of shares in millions outstanding during 2010?
schlumberger limited and subsidiaries shares of common stock issued in treasury shares outstanding ( stated in millions ) .

|  | Issued | In Treasury | Shares Outstanding |
| :--- | :--- | :--- | :--- |
| Balance, January 1, 2008 | 1,334 | (138) | 1,196 |
| Shares sold to optionees less shares exchanged | – | 5 | 5 |
| Shares issued under employee stock purchase plan | – | 2 | 2 |
| Stock repurchase program | – | (21) | (21) |
| Issued on conversions of debentures | – | 12 | 12 |
| Balance, December 31, 2008 | 1,334 | (140) | 1,194 |
| Shares sold to optionees less shares exchanged | – | 4 | 4 |
| Vesting of restricted stock | – | 1 | 1 |
| Shares issued under employee stock purchase plan | – | 4 | 4 |
| Stock repurchase program | – | (8) | (8) |
| Balance, December 31, 2009 | 1,334 | (139) | 1,195 |
| Acquisition of Smith International, Inc. | 100 | 76 | 176 |
| Shares sold to optionees less shares exchanged | – | 6 | 6 |
| Shares issued under employee stock purchase plan | – | 3 | 3 |
| Stock repurchase program | – | (27) | (27) |
| Issued on conversions of debentures | – | 8 | 8 |
| Balance, December 31, 2010 | 1,434 | (73) | 1,361 |

see the notes to consolidated financial statements part ii , item 8 .

beginning_balance = 1361
ending_balance = 1195
answer = (beginning_balance + ending_balance) / 2