I took the liberty of adding a zero and subtracting a question mark.
. . . but to your question:
The 144,000 are made up of two primary groups both of narrow ethnicity.
The bulk and first to be invited were apostate Jews who rejected the religion of their forefathers and joined a first century sect.
The last 30,000 or so were individuals primarily of European descent living in the United States during the latter part of the 19th century and the first third of the 20th century. The females of this group wore pillbox hats. The males wore the Sunday go-to-meeting clothes common to North America in those years.
Over the years since 1935 a few suffering schizophrenia, delusions of grandeur, plagued by visions or pure egotism stepped forward as "replacements" for some who proved unfaithful and had to be "lopped off."
An extremely small sampling of persons of color also got the calling.
tms