In The Clone Wars TV series it is mentioned that a bill is passed for the creation of 5 million more clone troopers.
Narrator: War on many fronts! While battles are fought by Clones in the field, a different war is waged in the Galactic Senate. As heavy losses add up, a group of senators led by Halle Burtoni of Kamino propose an escalation of troop production. Senator Padmé Amidala, recognizing that more troops will only prolong the fighting, works tirelessly with her allies to introduce a bill to cut down military spending and stop the creation of more Clone Troopers...
The Clone Wars, Season 2 Episode 15, "Senate Murders"
It is later reiterated about the creation of more Clone Troopers trying to be ordered with Padme again trying to fight back on it.
Halle Burtoni: Chancellor Palpatine, in light of this unprovoked attack on Coruscant and the vulnerabilities it raises, I propose the Republic purchase an additional 5 million clone troopers.
Padmé Amidala: Can't you all see this bill is shortsighted l? Millions of clones won't win this war. The only winner will be the Banking Clan. They want to pass this bill so badly, they're using scare tactics to sway votes.
The Clone Wars, Season 3 Episode 11, "Pursuit of Peace"