1000 days=little less than 3 years
JF17 production 50 in 6 years
therefore producing 150 requires 18 years at current production rate, i.e. 6 times the current given number(1000 days)
but since 1000 days is little less than 3 years, i rounded it off to 5 times.
But the first production JF-17 from the factory rolled out at the end of 2009.. so essentially its been closer to 5 years.. and its a ramping production line... which is how even the F-35 was rolled out. Hence the production rate cannot be taken as a constant.
Please refer to article for future reference on the reasons for slow production rate.
https://dl.dropboxusercontent.com/u/81032936/JFT_Article.pdf