Paraguay and Bolivia fought the Chaco War between 1932-1935, where around 5-8% of the Bolivian population was killed, and with Paraguay also suffering heavy losses. In Paraguay, this problem was exacerbated by the fact that Paraguay's population was still recovering after the Paraguayan War in 1864-1870 that had killed 60% of the population of Paraguay and left a female-to-male ratio of 4 to 1. It would therefore have been of interest for Paraguay and Bolivia to find ways of replenishing their population. I don't know whether the statistic you mentioned is true, but it would make sense that those nations would have encouraged immigration from Europe during that period.
Check out the book "The Real Odessa" by Uki Goni which revolves around Jewish immigration to South America, specifically Argentina. Wherever you read that stat it will unfortunately be thrown for a loop by what he concludes; that Argentina was intentionally denying Jewish visas (ties to the Nazi party) so many Jews were immigrating to neighboring countries and crossing the border for various motives.
Not true. Not at all... No jewish refugees came to Paraguay before WW2. In fact, Paraguay even had a Nazi party, and the anti-jew philosophy was even encouraged by the Governments.
Edit: There are many jews in Argentina, but not Paraguay. Bottom line is: this is not a true story, please post the link to where you read this.
Edit 2: I encourage you to look for the book called "Nazism and Facism in Paraguay", by the very respectable historian Alfredo Seiferheld, WHO I QUOTE "Nazis had in Paraguay two reasons to be proud of. The fact that the first Nazi Party in the american continent was formed here".
The other reason is related to a town called New Germania founded in Paraguay in 1887 by Friedrich Nietzsche`s brother in law: Bernard Foerster. It was supposed to be "a town untamed with jewish blood".
Anyways, here is a quote form a letter Nietzsche wrote to his sister: "Your late husband probably contaminated Paraguay so badly with his anti semitic plague, that this place must be such a bad place to live as it is Germany".
Edit 3: Of course, all this anti semitic official stand disapeared as soon as the Allies started winning WW2. And Paraguay "declared war on Germany". This, of course, was due to the pressure by the Allies and was done very reluctantly by the paraguayan government (which had strong simpathies for the Axis, i suggest you read about President Morinigo). But still, there is a joke the some friends of mine use to tell, that the Paraguayan declaration of war on Germany was the "key factor" in Germany`s surrender (Paraguay was one of the last countries to declare war on Germany, so you get the joke...).
TL;DR: This is not accurate, no refugees came to Paraguay. In fact, Paraguay was very pro-Nazi.