Baibek and Nazipa are getting married and are planning to combine their finances. Unfortunately, both of them are sales managers at a big company, so their salaries vary each month. They are trying to calculate whether they can afford a flat with a monthly payment of 1350$. Recently they are planning to spend only 30% of their total income on house payments. If Nazipas average monthly sales are 3000$ with a standard deviation of 500$ and Baibeks average monthly sales are 2000$ with a standard deviation of 1000$, and monthly sales are follows a normal sidtribution with a covariance between Baibek and Nazipa of 10000 $2, what percent of the time will they be able to spend less than 30% of their total income on the flat payment? Provide a numerical answer only.