1911 Census of England and Wales, General Report with Appendices, Table 83: " Counties with the Highest and Lowest Proportions of Families of Certain Sizes".

Families of less than 4 persons. Families of 4 to 6 persons. Families of over 6 persons.
County. Per 1,000
families.
County. Per 1,000
families.
County. Per 1,000
families.
Highest.   Highest.   Highest.  
Cardiganshire 530 Glamorganshire 466 Glamorganshire 239
Anglesey 483 Staffordshire 457 Monmouthshire 237
Cambridgeshire 471 Durham 454 Durham 226
Isle of Wight 471 Monmouthshire 452 Northumberland 196
Cornwall 468 Middlesex 451 Staffordshire 194
Suffolk, West 468 Derbyshire 449 Derbyshire 192
Carnarvonshire 467 Northumberland 449 Cumberland 191
Lowest.   Lowest.   Lowest.  
Glamorganshire 295 Cardiganshire 348 Anglesey 119
Monmouthshire 311 London 386 Isle of Wight 121
Durham 320 Suffolk, West 388 Cardiganshire 122
Staffordshire 349 Yorks, East Riding 396 Carnarvonshire 122
Northumberland 355 Anglesey 398 Cambridgeshire 125
Derbyshire 359 Oxfordshire 401 Cornwall 125
    Herefordshire 402 Merionethshire 126