Seeing as this is the name of a character from a British television series, it's no surprise that it gained a bit of a boost and peaked, at least in England & Wales, when the series was broadcast. Data from FreeBMD (w/ removal of duplicate records): 1975 - 9 births 1976 - 9 births 1977 - 50 births 1978 - 118 births 1979 - 106 births 1980 - 61 births 1981 - 47 births 1982 - 37 births 1983 - 23 births.
This name is also used in Spain.Based on statistics from INE involving living people in Spain, using only the statistics for those who were born inside the country, it was rare in the 1970s and most of the Davinias born in that decade were born in either Barcelona (Catalonia) or Las Palmas (Canary Islands). In the 1980s, it became more commonly used throughout Spain, less so by the 1990's onward.
Data from FreeBMD (w/ removal of duplicate records):
1975 - 9 births
1976 - 9 births
1977 - 50 births
1978 - 118 births
1979 - 106 births
1980 - 61 births
1981 - 47 births
1982 - 37 births
1983 - 23 births.