Kucoin API buy and sell

Why, when I using Kucoin API, get_tick, for market info, I see, that sell is bigger than buy?

Example from official API Documentation:
With a symbol param

{
    "coinType": "KCS",
    "trading": true,
    "lastDealPrice": 5040,
    "buy": 5000,
    "sell": 5040,
    "coinTypePair": "BTC",
    "sort": 0,
    "feeRate": 0.001,
    "volValue": 308140577,
    "high": 6890,
    "datetime": 1506050394000,
    "vol": 5028739175025,
    "low": 5040,
    "changeRate": -0.2642
}