Written evidence from Prof. Jakub Bijak (Professor of Statistical Demography at ¾ÅÉ«ÊÓÆµ), Dr Martin Hinsch (Research Fellow at ¾ÅÉ«ÊÓÆµ), Dr Sarah Nurse (Research Fellow at ¾ÅÉ«ÊÓÆµ), and Dr Toby Prike (Research Fellow at ¾ÅÉ«ÊÓÆµ)