The percentage of s- character on second carbon in $\mathrm{HC}\equiv \mathrm{C}-{\mathrm{CH}}_3$  is __________

[Step 1]:
% s-character in sp³ is 25 
% s-character in sp² is 33 
% s-character in sp is 50
[Step 2]:
 $\underset{\left(\mathrm{sp}\right)}{\mathrm{H}\stackrel{1}{\mathrm{C}}}\equiv \underset{\left(\mathrm{sp}\right)}{\stackrel{2}{\mathrm{C}}}-\underset{\left({\mathrm{sp}}^3\right)}{\stackrel{3}{{\mathrm{CH}}_3}}$
[Step 3]:
The hybridization of second carbon is sp and % s-character is 50.