Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Rank | City/Town | County | Region/Province | Population | Country |
| --- | --- | --- | --- | --- | --- |
| 1.0 | Dublin | County Dublin | Leinster | 505739.0 | Republic of Ireland |
| 2.0 | Liverpool | Merseyside | North West | 447500.0 | England |
| 3.0 | Belfast | County Antrim | Ulster | 276459.0 | Northern Ireland |
| 5.0 | Blackpool | Lancashire | North West | 142900.0 | England |
| 6.0 | Southport | Merseyside | North West | 99456.0 | England |
| 7.0 | Birkenhead | Merseyside | North West | 83729.0 | England |
| 8.0 | Bangor | County Down | Ulster | 76851.0 | Northern Ireland |
| 9.0 | Barrow-in-Furness | Cumbria | North West | 71980.0 | England |
| 10.0 | Wallasey | Merseyside | North West | 58710.0 | England |
| 11.0 | Crosby | Merseyside | North West | 51789.0 | England |
| 12.0 | Morecambe | Lancashire | North West | 45000.0 | England |
| 13.0 | Lytham St Annes | Lancashire | North West | 41330.0 | England |
| 14.0 | Drogheda | County Louth | Leinster | 35190.0 | Republic of Ireland |
| 15.0 | Dundalk | County Louth | Leinster | 35085.0 | Republic of Ireland |
| 16.0 | Rhyl | Denbighshire | Clwyd | 35000.0 | Wales |
| 17.0 | Bray | County Wicklow | Leinster | 31901.0 | Republic of Ireland |
| 18.0 | Thornton-Cleveleys | Lancashire | North West | 31157.0 | England |
| 19.0 | Colwyn Bay | Conwy | Clwyd | 30265.0 | Wales |
| 20.0 | Carrickfergus | County Antrim | Ulster | 27201.0 | Northern Ireland |
| 21.0 | Fleetwood | Lancashire | North West | 26840.0 | England |
| 22.0 | Douglas | N/A | Isle of Man | 26218.0 | Isle of Man |
| 20.0 | Workington | Cumbria | North West | 25978.0 | England |
| 23.0 | Whitehaven | Cumbria | North West | 25500.0 | England |
| 24.0 | Dún Laoghaire | Dún Laoghaire–Rathdown | Leinster | 23857.0 | Republic of Ireland |
| 25.0 | Llandudno | Conwy | Clwyd | 20090.0 | Wales |
| 26.0 | Larne | County Antrim | Ulster | 18228.0 | Northern Ireland |
Question:
When 142900 is the population what is the highest rank?
Answer:
5.0