Factbox - Indonesia's election year

JAKARTA (Reuters) - Indonesia holds parliamentary and presidential elections this year in what could bring major change to the way the world's third largest democracy is run. Both elections are held every five years.

Current President Susilo Bambang Yudhoyono is in the last year of his second term and is barred by the constitution from running again.

DATES

March 16 - Campaigning for the parliamentary election starts

April 9 - Parliamentary election

April 26 - Vote counting starts, until May 6

May 7 - Official result due to be declared

July 9 - Presidential election

July 26 - Winner due to be announced, if no runoff

September 9 - Presidential election runoff if no clear winner in the first round

September 26 - Winner due to be announced

October 20 - New president inaugurated

REQUIREMENTS

A party, or coalition of parties, must win at least 25 percent of the national vote or 20 percent of parliamentary seats to nominate a presidential candidate.

The candidate must win 50 percent of the national vote and 20 percent of the vote in over half of the 34 provinces to be elected president.

If no-one wins that many votes, a run-off is held between the two candidates with the most votes. The winner is decided by a simple majority.

PARTIES

There are 12 parties standing in the parliamentary election.

According to opinion polls, the parties expected to dominate are the Indonesian Democratic-Party Struggle (PDI-P), Golkar and Gerindra. PDI-P received a major boost on Friday when it named the hugely popular governor of Jakarta as its candidate for the presidential election.

The current ruling Democrat Party of Yudhoyono is expected to struggle to win votes in the double digits.

NUMBERS

Total registered voters: 186.5 million

Of the total, 29 percent are aged 17-29 years. Eleven percent will vote for the first time.

Voter turnout in 2009 was 74 percent.

For parliament, 560 seats are up for grabs, contested by 6,607 candidates.

In addition, there will be elections for 132 seats for regional representatives at the national level, 2,112 provincial parliamentary seats, and 16,895 seats for district level legislative assemblies.

(Reporting by Anastasia Arvirianty and Kanupriya Kapoor. Writing by Jonathan Thatcher. Editing by Dean Yates)