There a lot of altcoins in 2015 as well, but a lot of them has seemed to survive till now. So 95% is a wrong assumption, somewhere near 75% of alts will be gone might be a realistic assumption.
2015, 16 and 17 are not equal. 2018 will be much more difficult for many altcoins. so 95% is a fairly likely percentage. besides, those altcoins about which you speak is about 10% of all. Someone should count real numbers of it for statistic