More than 23 census records are available for the Blackadar family, from both 1901 and 1911.
Sample 1901 Yarmouth census records about the Blackadar family available from Ancestry.ca:
A Blackadar family household of at least 9 members residing in the district of Yarmouth was recorded in 1901. The head of household, John C Blackadar, was born in Nova Scotia in 1835. He identified his heritage as English. By 1901, at the age of 66, he had an occupation that was recorded as "Lumberman". John's wife was Annie Blackadar, who was 59 years old. Annie was born in Nova Scotia in 1842. She also identified her heritage as English. John and Annie had 7 children, 4 boys and 3 girls. In 1876 their eldest child, a boy named Rose, was born. Two years later, in 1878, when John was 43 years old and Annie was 36 years old their second child, this time a daughter, who was named Flora, was born. Then, in 1880, with their two children ages 4 years and 2 years, their third child, James, was born. In 1901 another son, their fourth child and third boy, Thomas, was born. With four other children in the household, their fifth child and fourth boy, Wallace, was born in 1885. He was followed by 2 more children: their daughter Lizzie, born in 1886; and their daughter Lena, born in 1888. Thus, at the time of the 1901 census, this Blackadar family household was filled with 7 children whose ages were 12, 14, 16, 19, 21, 22, and 25 years.