Key facts about oil production in Azerbaijan
Oil-producing Azerbaijan is voting on whether to scrap the country's two-term presidential limit and give Ilham
Aliyev the chance to rule beyond 2013. The opposition and rights groups have criticised the move.
Here are some key facts about the country:
Azerbaijan, a former Soviet republic, lies at a strategic crossroads between East and West, sandwiched between Iran and Russia and straddling a region emerging as a key transit route for oil and gas from Central Asia to Europe.
It also borders Georgia, Armenia and Turkey.
8.7 mm, mostly Shi'ite Muslims. They speak Azeri, which is closely related to Turkish.
Russian is also widely spoken as a legacy of the Soviet Union and business ties with Russia, particularly in the capital, Baku.
With a BP-led oil and gas pipeline to the Mediterranean, Azerbaijan is a hub for exporting Caspian Sea crude and natural gas to world markets. Energy markets see Caspian oil and gas as keyto Europe's policy of diversifying energy supplies.
GDP grew by an average of more than 20 % per year between 2003 and 2007, making Azerbaijan's economy one of the world's fastest growing. The federal budget multiplied tenfold -- from $ 1.2 bn to $ 12 bn -- over the last five years. Even with the onset of the global economic crisis, GDP is forecast to grow 10 % in 2009, slightly down on 10.8 % in 2008. Azerbaijan has a state oil fund of $ 11.2 bn.
Rights groups accuse the authorities of curbing democracy and media freedoms and point to a personality cult around Ilham Aliyev's father and long-serving leader Heydar that they say makes dissent dangerous.
Azerbaijan's authorities say they are committed to international standards of democracy but that they have an obligation to protect the country from forces they say are trying to sow instability.
Ethnic Armenian separatists, backed by Armenia, fought a war in the 1990s to throw off Azerbaijan's control over the mountainous Nagorno-Karabakh region. An estimated 30,000 people were killed.
A peace accord has never been signed, and the ceasefire is frequently tested by exchanges of fire across the frontline. Armenia backs Nagorno-Karabakh's demand for independence, something Azerbaijan says it can never have.