Add changelog entry

CHANGELOG.md

@@ -6,6 +6,36 @@ A breaking change will get clearly marked in this log.
 
 ## Unreleased
 
+### Added
+- `rpc.Server` now has a `getFeeStats` method which retrieves fee statistics for a previous chunk of ledgers to provide users with a way to provide informed decisions about getting their transactions included in the following ledgers ([#998](https://github.com/stellar/js-stellar-sdk/issues/998)):
+
+```typescript
+export interface GetFeeStatsResponse {
+	sorobanInclusionFee: FeeDistribution;
+	inclusionFee: FeeDistribution;
+	latestLedger: number; // uint32
+}
+
+interface FeeDistribution {
+	max: string;  // uint64
+	min: string;  // uint64
+	mode: string; // uint64
+	p10: string;  // uint64
+	p20: string;  // uint64
+	p30: string;  // uint64
+	p40: string;  // uint64
+	p50: string;  // uint64
+	p60: string;  // uint64
+	p70: string;  // uint64
+	p80: string;  // uint64
+	p90: string;  // uint64
+	p95: string;  // uint64
+	p99: string;  // uint64
+	transactionCount: string; // uint32
+	ledgerCount: number;      // uint32
+}
+```
+
 
 ## [v12.1.0](https://github.com/stellar/js-stellar-sdk/compare/v12.0.1...v12.1.0)