Jan 15 (Reuters) - Citigroup Inc reported a 7% decline in fourth-quarter profit on Friday but easily beat Wall Street expectations, as an improving economic outlook allowed it to release cash it had previously set aside for bad loans. The New York-based bank earned $4.63 billion, or $2.08 a share, down from $5 billion, or $2.15 a share, a year earlier. Analysts on average had expected profit of $1.34 per share, according to Refinitiv data.