HONG KONG — As Hong Kong marked the 18th anniversary on Wednesday of its handover from Britain to China, thousands of residents took to the streets in what has become an annual tradition of rallying for greater democracy. But in contrast to last year, when by the organizers’ estimate the turnout was more than half a million, the crowd this year was tiny.

Its notably smaller size — the police estimate was 20,000, which would make it the smallest since 2008 — seemed to speak to the demonstrators’ exhaustion, after months of intense but unfruitful political bickering, and to their frustration over the way ahead.

“I’m so upset. None of my friends would come with me this year,” said Lam Ip, a 30-year-old civil servant who in the end came on his own. “They said that the government wouldn’t even give in to the massive protests last year. ‘Why would they fear a march?’ ”

Daisy Chan, a spokeswoman for the march’s organizer, the Civil Human Rights Front, said: “There’s no longer any urgent topics on the table that could draw many people to the streets. We need some time to contemplate our next step.”