Kurdish Peshmerga forces stand guard in the oil-rich city of Kirkuk against Islamic State of Iraq and the Levant (ISIL).

It is not a corporation and does not have shareholders, but the military success and brutality of the jihadi group surging through Iraq have been recorded with the level of precision often reserved for company accounts.

Since 2012 the Islamic State of Iraq and the Levant, (known as Isis) has issued annual reports, outlining in numerical and geographical detail its operations – the number of bombings, assassinations, checkpoints, suicide missions, cities taken over and even "apostates" converted to the Isis cause.

In 2013 alone, the group's report claimed nearly 10,000 operations in Iraq: 1,000 assassinations, 4,000 improvised explosive devices planted and hundreds of radical prisoners freed. In the same year it claimed hundreds of "apostates" had been turned.

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Called al-Naba – the News – the reports for 2012 and 2013 (a year in which 8,000 civilians died in Iraq) have been analyzed by the US-based Institute for the Study of War, which corroborates much of the information they contain. Isis's aim appears to be to demonstrate its record to potential donors.

The reports paint a picture of an organisation that analysts say is not so much the ragtag terrorist band depicted by Iraqi officials but more of an organised military structure with a clear political strategy to set up a Sunni sectarian state – and one with several of the hallmarks of a corporate entity.

"The reports provide measures of performance in the way you roll out details for donors," said Jessica Lewis, director of research at the Institute for the Study of War. "They affirm that the organisation operates like an army and that it has state-building ambitions."

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Nigel Inkster, former assistant chief of UK intelligence service MI6, and now director of transnational threats at the International Institute for Strategic Studies, said: "They produce [them] almost like a company, with details of martyrdom operations and targets. You have a clear overlay of structure, planning and strategy to the organisation."

Isis's ambition had been gradually unfolding over the past year but in the past week it has taken shape with lightning speed, with the territory under its control stretching from east of the Syrian city of Aleppo, across northern Iraq.

What is clear from the documents is that Isis's campaign to control Sunni-populated Iraqi territory – and its capture of the second city of Mosul – should not have startled either the Shia-led government in Baghdad or its western allies. They highlight the extent to which Nineveh, the province that includes Mosul, seized last week, has long been a target.

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The Institute for the Study of War's analysis shows that 30 per cent of Isis attacks in 2012 and 2013 were in Nineveh, making the province the "primary attack zone" for the group.

"The number of attacks [in Iraq] has been rising steadily for months," said John Drake, senior Iraq analyst at security firm AKE. "Now there are over a hundred people being killed every week. Isis has been getting stronger and stronger."