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:
| 2011 rank | 2010 rank | 2009 rank | 2008 rank | 2007 rank | Company (country) | 2011 arms sales (US$ m.) | 2010 arms sales (US$ m.) | 2009 arms sales (US$ m.) | 2008 arms sales (US$ m.) | 2007 arms sales (US$ m.) | Arms sales as share of company’s total sales (%), |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 1 | 1 | 2 | 3 | Lockheed Martin | 36270 | 35730 | 33430 | 29880 | 29400 | 78 |
| 2 | 3 | 3 | 3 | 1 | Boeing | 31830 | 31360 | 32300 | 29200 | 30480 | 46 |
| 3 | 2 | 2 | 1 | 2 | BAE Systems | 29150 | 32880 | 33250 | 32420 | 29860 | 95 |
| 4 | 5 | 5 | 5 | 5 | General Dynamics | 23760 | 23940 | 25590 | 22780 | 21520 | 73 |
| 5 | 6 | 6 | 6 | 6 | Raytheon | 22470 | 22980 | 21030 | 23080 | 19540 | 90 |
| 6 | 4 | 4 | 4 | 4 | Northrop Grumman | 21390 | 28150 | 27000 | 26090 | 24600 | 81 |
| 7 | 7 | 7 | 7 | 7 | Airbus Group | 16390 | 16360 | 17900 | 15930 | 13100 | 24 |
| 8 | 8 | 8 | 8 | 9 | Finmeccanica | 14560 | 14410 | 13280 | 13020 | 9850 | 60 |
| 9 | 9 | 9 | 9 | 8 | L-3 Communications | 12520 | 13070 | 13010 | 12160 | 11240 | 83 |
| 10 | 10 | 10 | 11 | 11 | United Technologies Corporation | 11640 | 11410 | 11110 | 9980 | 8760 | 20 |
| 11 | 11 | 11 | 10 | 10 | Thales Group | 9480 | 9950 | 10200 | 10760 | 9350 | 52 |
| 12 | 12 | 12 | 12 | 12 | SAIC | 7940 | 8230 | 8030 | 7350 | 6250 | 75 |
| 13 | - | - | - | - | Huntington Ingalls Industries | 6380 | - | - | - | - | 97 |
| 14 | 15 | 14 | 15 | 15 | Honeywell | 5280 | 5400 | 5380 | 5310 | 5020 | 14 |
| 15 | 16 | 16 | 25 | 14 | SAFRAN | 5240 | 4800 | 4740 | 3020 | 5230 | 32 |
| 16 | 14 | 13 | 14 | 13 | Computer Sciences Corp. | 4860 | 5940 | 6050 | 5710 | 5420 | 31 |
| 17 | 17 | 19 | 17 | 17 | Rolls-Royce | 4670 | 4330 | 4140 | 4720 | 4580 | 26 |
| 18 | 21 | - | - | - | United Aircraft Corporation | 4440 | 3440 | - | - | - | 80 |
| 19 | 13 | 27 | 37 | 45 | Oshkosh Corporation | 4370 | 7080 | 2770 | 2070 | 1570 | 58 |
| 20 | 18 | 18 | 22 | 20 | General Electric | 4100 | 4300 | 4700 | 3650 | 3460 | 3 |
| 21 | 19 | 17 | 16 | 19 | ITT Corp. | 4020 | 4000 | 4730 | 5170 | 3850 | 69 |
| 22 | 20 | 22 | 18 | 23 | Almaz-Antey | 3690 | 3950 | 3260 | 4340 | 2780 | 85 |
Question:
how many different countries are listed?
Answer:
6