Pan-democratic candidates may suffer at the polls from marked shifts in the age groups of voters registered for September's legislative election, analysts said yesterday. The latest figures were published by the Registration and Electoral Office yesterday. They show the number of voters in their 30s and 40s has dropped by more than 10 per cent since 2008. The number of elderly voters has grown sharply, notably with a 50 per cent jump in the 61-65 age group. Yesterday was also the first day of the two-week nomination period for September's Legislative Council election. Political heavyweights and fledgling challengers alike were eager to submit their nomination forms: the 39 handed in was the highest first-day number since 1997. A total of 3,466,175 voters are eligible to vote in the September 9 election, 2.8 per cent more than in the 2008 election, the electoral office reported. The increase was driven largely by big rises in young and elderly voters. Voters aged 18 to 20 are up 40.9 per cent, while the number aged 61 to 65 is up 49.9 per cent. But the numbers in between dwindled. There was a drop of 17 per cent from 2008 in registered voters who are in their 40s; the decline in the number of voters aged 41 to 45 was even more marked, at 21.7 per cent. The drop was smaller for those in their 30s: there are 4 per cent fewer voters aged 36 to 40 and 11 per cent fewer aged 31 to 35. Observers said the big rise in voters 61 and over showed that the Beijing-loyalist camp had worked hard at getting them registered. 'Traditionally, the elderly are the major support base of the pro-establishment camp, which has more resources for district work,' said Ma Ngok, associate professor in Chinese University's department of government and public administration. 'The group that has seen a big increase may not be like normal voters, who are really interested in casting a ballot. But the pro-establishment parties are always more organised, and better at getting them to register and vote.' The figures may suggest an advantage for the pro-government Democratic Alliance for the Betterment and Progress of Hong Kong and Federation of Trade Unions, Ma said. As for the shrinking number of middle-aged voters - who tend to favour pan-democrats - Ma pointed out that they tend to move home a lot, and some may have forgotten to re-register as voters. 'Those who don't care about renewing their registration may not be keen on politics. They may not come out and vote in the election anyway,' Ma said. Political observer James Sung Lap-kung, of City University, said radical pan-democrat parties such as People Power and the League of Social Democrats were likely to gain from the increase of young voters. The number of Legco seats increases from 60 to 70 for the September election, and a record number of nominations is expected. The registered electorate is 2.7 per cent smaller than that for November's district council polls, largely because 216,000 people lost their voting rights after ignoring the electoral office's requests to validate their addresses as part of a clampdown on vote-rigging. The electoral office sent 296,000 letters to voters whose addresses were in doubt, and gave them six weeks to reply.