But England still has one of the highest rates of the disease in Western Europe.
Prof Hawking, who had motor neurone disease, died on 14 March, aged 76, at his home in Cambridge.
The Duchess of Devonshire says she is "thrilled" by the work, which has taken 10 years.
The mother whose morning sickness has never gone away
The engineering giant with 'short man syndrome'
The competition to "cheer up London"
Showcasing the best images sent to us from around England
Who abandoned this little girl on a hillside with her hands tied?
'I forget my PE kit deliberately'
Rain stops play after 17 balls of day three as New Zealand bat on against England in the first Test in Auckland - follow live text and TMS commentary.
Why do we change the clocks?
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