$ perl -Mstrict -Mwarnings -E '
> my %hash;
> say scalar %hash;
> for ( q{a} .. q{z} )
> {
>     $hash{ $_ } = 1;
>     say qq{$_ - @{ [ scalar %hash ] }};
> }'
0
a - 1/8
b - 2/8
c - 3/8
d - 4/8
e - 5/8
f - 6/8
g - 6/8
h - 7/16
i - 8/16
j - 9/16
k - 9/16
l - 10/16
m - 10/16
n - 11/16
o - 11/16
p - 14/32
q - 14/32
r - 14/32
s - 15/32
t - 15/32
u - 16/32
v - 16/32
w - 17/32
x - 17/32
y - 18/32
z - 19/32
$