Average per capita income before Saddam took over in 1979 = US$12,300
Average per capita income 10-years later = US$750
Average per capita income before the 2003 invasion = US$507
Average per capita income today = US$4,500

Had Saddam remained in power and had he maintained his predation on the population and citizenry of Iraq the number of dead over the last 10 years would be somewhere in between 560,000 and 1,000,000. Instead the invasion and its aftermath caused ~150,000 deaths - 78% of whom were Iraqis killed by fellow Iraqis or "visiting" fellow Muslims.

Given that Saddam would have found out about Iran's "secret" uranium enrichment plants at Qum and Natanz then my guess would lean towards the higher figure of dead as by now we would, in all likelihood, be into the fifth year of the Second Iran/Iraq War - there is no way that Saddam Hussein would sit back and permit Iran to acquire any sort of nuclear capability.

If you think what Bashar Al-Assad (A fellow Ba'athist) is doing in Syria in response to his little "Arab Spring" Revolution is bad - Just think how Saddam and his Sons would have handled any "Arab Spring" in Iraq - for those with no imagination - they would make what Assad has done look like the benign and benevolent attentions of a Boy Scout (In Syria in two years the death toll stands at around 70,000 - In just over one month in 1991 Saddam killed 200,000 Shia Arabs in the South of Iraq).