Intro
As we all know, Ahmadis always lie about the amount of Ahmadis in the world, they even talk down to the Lahori-Ahmadis in this regard.  Well, in 1950, the Ahmadiyya Khalifa admitted to all of this.  See the below, taken from here: http://www.muslim.org/qadis/95-3.htm

“The truth is that, although we have never conducted a count, in our estimate the number of people in the Jama’at is approximately two hundred thousand. We cannot see more than this. It is possible that if the branches overseas are taken into account this number may reach three hundred thousand. The utmost limit, which it is absolutely impossible to exceed, is four hundred thousand. But some people in the Jama’at have now reached the stage in their exaggeration that, when saying how many they are, they give a figure of up to two and a half million. ” . . .

The falsehood which is now uttered, that we number two and a half million, has no advantage but instead leads to two drawbacks. One is that the man who says this, gives up propagation work because he thinks that there are two and a half million people doing this work, and so it makes no difference if he does not do it. The second drawback is that such a man is slow to pay his contributions because he thinks that there are two and a half million people contributing, and so it makes no difference if he does not pay his contributions.” (Friday khutba, 18 August 1950, reproduced in Al-Fazl, 5 September 1950.)

https://ahmadiyyafactcheckblog.wordpress.com/2017/07/30/ahmadis-always-lie-about-conversions-at-the-ukjalsa/

See here for the full reference: (The Light & Islamic Review: Vol.72, No. 3; May-June 1995; p. 18-19)

MGA also said
“I am never pleased by the mere size of the Jama’at. Although at present its size is 400,000 or more, a real Jama’at is not one where people merely take the bai’at with their hands. The Jama’at can only deserve to be called the Jama’at in the true sense if people adhere to the real purpose of the bai’at, if they actually undergo a thorough transformation for the good, and their lives are cleansed of the pollution of sin.”  (Malfuzat, vol. x, p.136.)