The Total column shows the total number of people in that county or town with this surname. For example, there were 3,683 people called OWEN in Anglesey / Sir Fon at the time of the 1881 census.
The Frequency column shows the percentage of people in this county or town with this surname. For example, a frequency of 7.1137 in Anglesey / Sir Fon means that 7.1137% of the people in Anglesey / Sir Fon on census day were called OWEN.
The Index column shows the relative probability of finding someone called OWEN in this county or town, compared with the probability of finding them anywhere in Britain as a whole. An index of 1 means that if you pick someone at random from this county or town, you have exactly the same probability of picking someone called OWEN as if you picked at random from the whole of the UK. Where the index is higher than 1, then you are more likely to find someone called OWEN here than if you picked from the UK as a whole, and where it's lower then you are less likely. The actual figure shows the level of probability - for example, a figure of 2 would indicate that you are twice as likely to find someone called OWEN here than in the UK as a whole, and 10 would make it ten times as likely. The value of 59.94 in Anglesey / Sir Fon means that you are 59.94 times as likely to find someone with the surname of OWEN in Anglesey / Sir Fon than you would be in the whole of the UK.