Technically, the number has either remained the same, or has decreased slightly as stuff burns up in our atmosphere.
;’)
The early warnings we get now make the numbers seem larger — IOW, objects were hummin’ by all the time, and we were down here, blissfully unaware, except when large boloids made it all or most of the way through, as happened at Tunguska in 1908, in the Amazon back in the 1930s, in Greenland in the 1990s (or was it 1980s?), out west over a national park in the early 1970s, in the Indian Ocean in the 1970s (that one is often still attributed to a South African atomic bomb test, but if that’s the case, where’s the South African bomb?), and of course, there are the Small Comets which strike the upper atmosphere continously.
http://www.freerepublic.com/focus/bloggers/1250694/posts
Louis Frank was hired to confirm what our early warning system for incoming nukes appeared to be seeing — upper atmosphere explosions which were natural and had to be differentiated from incoming Soviet missiles. Getting a second set of eyes working on this (without telling him why) helped all of us, but probably didn’t help his career.
http://www.freerepublic.com/focus/bloggers/1250694/posts?page=17#17
The one over the Indian Ocean had the double flash that was detected by the “bhangmeter” on one of the Vela satellites. Only an atmospheric nuclear explosion can cause such a double flash - two light intensity spikes, separated by a period of time when the shock wave radius has some opacity blocking out the light of the fireball. The rate of increase in light intensity I (dI/dt) would be much higher than a meteor. The bhangmeter (a special photometer designed to detect such “double flashes”) can tell the difference.
South Africa did acknowledge having a nuclear program (remember, Cubans and Angolans acting as Soviet surrogates where making incursions into South Africa during the Cold War), and has dismantled their program.