Isaac Carrasco and his two daughters dutifully adorned the graves of several relatives with beds of marigolds and crosses made of red flowers for Mexico's Day of the Dead.

But the nearby tombstones of his grandparents were bare and surrounded by metal bars, left this way by his aunts, who no longer mark the annual ritual.

Like a growing number of Mexicans, Carrasco's aunts became Protestant and no longer believe in a tradition that dates back from the Aztec era and was later fused with Catholic beliefs.

"I would be sad if my daughters forgot about by grave like the way they abandoned by grandparents' graves," Carrasco, a farmer in his 60s, said at the San Lucas Cemetery in the central Mexican town of Tlacotepec.

All across Mexico, people decorated graves and put up altars in their homes on Thursday and Friday, placing photos of their loved ones along with gifts such as sugar skulls, tequila and cigars.

Mexicans believe that the souls of the deceased return during the night to enjoy this feast with their loved ones. They sing and laugh, and some even sleep in the cemetery next to portable stoves with burning incense.

The cemetery of Tlacotepec, a town of 10,000 people, is one of the oldest in the central Mexican region, which is known of its chile poblano -- a mild chili pepper -- and is home to the Popocatepetl and Iztaccihuatl volcanoes.

Around 10 percent of the nearly 1,000 graves in the San Lucas Cemetery were not decorated this year, according to the local priest, Marco Antonio Ramos. The number of graves without decorations has steadily increased over the last five years, he said.

Catholicism has lost some ground in Mexico with the rise of Protestantism.

Over the last decade, the number of Catholics has dropped from 88 percent to nearly 84 percent of the population, according to a document released by the Archdiocese of Mexico before the March visit of Pope Benedict XVI.

There are now 11 million Protestants in Mexico, compared to almost 93 million Catholics in a country of 112 million people. Mexico still has the second biggest Catholic population in Latin America after Brazil.

"We will cling to this tradition," Carrasco said as he dug a hole in the earth with a machete to place a candle. "Maybe one soul has already come to drink his mezcal," he said, referring to the booze made from the maguey plant.

At another grave site, Emiliano Chino and his large family held a party of around 20 dead relatives, drinking a warm punch, singing and dancing into the evening.

"How else are we going to transmit the tradition to the young ones?" Chino said. "We joke around and the night goes by fast."