FACTBOX: How Greeks vote for new parliament

(Reuters) - Greeks voted on Sunday in a parliamentary election seen as crucial for the country's reform path.

Here are some key facts about the election:

- Some 9.8 million Greeks have the right to vote, out of a total population of 10.9 million. About 5 million of them are women, while 490,000 young Greeks will vote for the first time.

- Polls opened at 7 a.m. (midnight EDT) and close at 7 p.m. (12:00 p.m. EDT). The vote is compulsory.

- No opinion polls have been published since Sept 1, the legal blackout date. Exit polls are allowed to be published after polls close and the first official results are expected a couple of hours later.

- A total of 21 parties are contesting the election. A party must pass a 3 percent of the vote threshold to enter parliament.

- The 300 parliamentary deputies are elected for a 4-year term. Twelve members of parliament are not elected directly by the voters but as "national deputies" from nationwide party tickets, depending on the parties' percentages.

- Greece is divided into 56 local constituencies. The number of representatives elected in each constituency depends on the region's population. The Athens second constituency is the largest with 42 seats.

- Under the new electoral system of "reinforced proportionality", enacted early 2004, 40 seats are given as a bonus to the party with the most votes while the remaining 260 seats are distributed proportionally depending on each party's percentage. The law helps give the winner a comfortable majority.

- If no party wins a clear majority, the president begins a process of giving parties 3-day mandates to see if they can form coalitions. If none succeeds, elections are called in 30 days.

- According to recent opinion polls, five parties are expected to enter parliament; the conservative New Democracy, the socialist PASOK, the Greek communist KKE, the Left Coalition SYN and the far-right LA.O.S.