Women in Shanghai may find it increasingly difficult to find a spouse, Shanghai Morning Post reported Friday.

The number of single women in Shanghai is four times their male counterparts, according to a survey by the Shanghai Matchmaking Industry Association. And most of the women are between 30 and 35, the paper said.

More than 1.8 million unmarried people seek out matchmaking agencies for help, but only 20 percent find their mates through the intermediaries, said Zhou Juemin, head of the association.

Many single women are particular about picking a partner, even if they are not so young. But most well-off single men with cars and houses are above 35 and prefer young women around 25, Zhou said.

Meanwhile, being unmarried seems to upset the parents more than the singles themselves, as "most of the phone calls we receive every day are from parents," Zhou said.