Growth in Saudi Arabia's non-oil private sector slowed slightly in February, reaching its lowest level in nine months, as competitive pressures weighed on expansion, a survey showed on Tuesday, although demand remained strong. The seasonally adjusted Riyad Bank Saudi Arabia Purchasing Managers' Index (PMI) slipped to a reading of 56.1 in February from January's 56.3, but remained well above the 50.0 threshold that separates growth from contraction.