On January 1st, 2020, an investment portfolio was valued at $10,000. Due to COVID-19 concerns, world markets plummetted in value in early 2020, and as of April 1st, 2020 the portfolio had a value which was only 75% of its value at the beginning of the year. Stock markets have proven to be resilient over time, so assuming that markets recover at an annual rate of 7% compounded quarterly, how long will it take for the portfolio to recover to its January 1st, 2020 value? Express your answer in years rounded to one decimal point.