UMVUE of an exponential mean

Suppose that the lifetimes (in months) of bulbs manufactured by a company have an $\mathrm{Exp}(\lambda)$ distribution, where $\lambda>0$. A random sample of size $10$ taken from the bulbs manufactured by the company yields the sample mean lifetime $\bar x=3.52$ months. Then the uniformly minimum variance unbiased estimate of $\frac1\lambda$ based on this sample is equal to __________ months (round off to 2 decimal places)