Sure, the math isn't that complicated but i'll give the caveat that I don't manage money in this space so its a bit outside my area of expertise.
THe annual premium is approx the premium paid to cover the expected loss, so:
spread = (prob_of_default_annual * (1-recovery_rate)
We have a spread of 0.06 and a recovery_rate of 0.4
so the annual probability of default is about 0.10
Now converting that to 5 year we have
prob_of_default5y = 1 - (1-pd_annual)^5
Which gives about 40%.
And if you look at the cds spreads across various bond ratings you'll see they look like
Rating || 5y CDS Spread || 5 yr default prob
BBB 60-120bps 1-3%
BB 150-250bps 5-15%
B 400-700bps 25-34%
CCC 700-1200bps 35-60%