More than 48 census records are available for the DeCoste family, from both 1901 and 1911.
Sample 1901 Vaudreuil census records about the DeCoste family available from Ancestry.ca:
A DeCoste family household of at least 9 members residing in the district of Vaudreuil was recorded in 1901. The head of household, Joseph DeCoste, was born in Quebec in 1848. He identified his heritage as French. By 1901, at the age of 52, he had an occupation that was recorded as "Journalier". Joseph's wife was Edesse DeCoste, who was 41 years old. Edesse was born in Quebec in 1859. She also identified her heritage as French. Joseph and Edesse had 7 children, 3 boys and 4 girls. In 1883 their eldest child, a boy named Oscar, was born. Four years later, in 1887, when Joseph was 39 years old and Edesse was 28 years old their second child, this time a daughter, who was named Blandine, was born. Then, in 1889, with their two children ages 6 years and 2 years, their third child, Delima, was born. In 1901 another son, their fourth child and second boy, Raoul, was born. With four other children in the household, their fifth child and third girl, Angelina, was born in 1894. She was followed by 2 more children: their son Emil, born in 1896; and their daughter Marie Jeanne, born in 1900. Thus, at the time of the 1901 census, this DeCoste family household was filled with 7 children whose ages were 1, 5, 6, 10, 11, 13, and 17 years.