There's a thread on this forum that aggregates delivery success statistics. Overall, 96.5% of packages arrive safely, but that number doesn't tell the whole story. A package is much more likely to get seized in customs, sot he delivery success rate there may be 93-95% while delivery success for domestic shipping is higher than 99%. For small amounts, they won't do a controlled delivery. They'll send you a letter. So your best bet is to order small and domestic.