Steve Newton’s “Lost for the Cause” does a thorough breakdown of the Confederate draft (to the extent the surviving figures allow), and finds that the number of draftees was always much less than the number of volunteers. Best estimates have the total number of Confederate soldiers at around 1 million, and many joined up prior to the institution of the draft. The head of the Confederate Conscription Bureau, General Preston, estimated that about 1/3 of the army additions after April 1862 were draftees.
By way of comparison, Union conscription provided only 6 to 8 percent of all Union soldiers and the North never resorted to extending enlistments. The Union army could have faded away almost completely in the summer of 1864 when the 3 year enlistments ran out, and the fact that it didn't is a testament to the dedication of the Union soldier.
If I may add a clarification, it has been said:
“However, since in April 1862 the confederate government also forcibly extended the enlistments of all the current soldiers for the duration of the war one could say that a much higher percentage of the confederate army than that were there because they had to be.”
Is that a true conclusion? Not really. Truthfully, the Union had their own Draft Act, which also forced northerners into conscription in July 1863, and March, July, and December of 1864.
The United States War Department data shows that of the 249,259 18 to 35 year old men whose names were drawn for the draft, only about 6% served. The rest evaded by paying commutation or hiring a substitute. (Confederate legislation banned substitution in 1863).
There does not appear to be a case for a “testament to the dedication of the Union soldier” since 94% of the Union draftees refused to serve.