When Have 17-year Trends Been Significant?

Earlier I found that the 17-year trend of HadCRUT4 has been statistically significant only 49% of time (with lag-1 autocorrelation) since it began in 1850.

Here are those times -- when that trend has been statistically significant at the 95% confidence level, and the value of that trend.

At the present time, this particular trend is not statistically significant, with this level of autocorrelation factored in, and it hasn't been since March 2013. (I find that, instead, its ss=85%.)