When selecting a routing scheme for an ad hoc network, we must consider security as well as the network performance. In this paper, we numerically analyze the route availability of the multi-path routing schemes (MPRS) against malicious actions. After defining the class of multi-path routing schemes and the attack model, we compare the expectation of routes disruption of the MPRS with the single path routing scheme (SPRS). Our results show that the MPRS is twice as robust as the SPRS.