I stumbled upon these numbers for the demographic history of England.
I would have imagined, that shortly after the Black Death the population would have reached a low-point for the second Millennium. How was it even lower in the 16th century ?
This is a good paper on it:
http://www.basvanleeuwen.net/bestanden/medievalpopulation7.pdf
Although such a catastrophic decline was almost certainly followed by an immediate rebound, further national outbreaks of plague in 1361-62, 1369 and 1375 progressively eroded the population’s capacity to replace itself and ensured that by 1377 nearly half of the population had been wiped out (Hatcher, 1977: 25).
The manorial evidence suggests that after the bounce-back between 1351 and 1377, the downward trend from the 1348 peak resumed at a substantial rate between 1377 and 1400, and continued at a reduced rate to the middle of the fifteenth century. One way of understanding this trend would be if the later plague outbreaks disproportionately affected younger age groups, thus making it difficult for the population to rebound through increased fertility (Hatcher, 1977: 58-62).
Basically there were multiple outbreaks in the second half of the 14th century, and population continued to decline during the early 15th due to social and demographic disruption, and such population crashes are slow to recover from.