I have following data about early neonatal deaths:

data early;
input ga alive mort total;
datalines;
22 23 19 42
23 522 214 736
24 1430 323 1753
25 1942 243 2185
26 2490 174 2664
27 3143 127 3270
28 4030 126 4156
29 4792 96 4888
30 6201 88 6289
31 7971 85 8056
32 5401 43 5444
;
run;

ga: gestational age in completed weeks
alive: newborns surviving the early neonatal period
mort: newborns not surviving the early neonatal period
total: alive + mort

I computed 95% CI on the proportions of mort/total as well.
Graphically this looks exponential.

How should I model these proportions, without loosing information regarding the numbers of observations?

Graphically