Evidence Code section 1291, subdivision (a)(2), provides that former testimony is admissible if the declarant is unavailable and "the party against whom the former testimony is offered was a party to the action or proceeding in which the testimony was given and had the right and opportunity to cross-examine the declarant with an interest and motive similar to that which he has at the hearing." A declarant is unavailable if he or she is "absent from the hearing and the proponent of his or her statement has exercised reasonable diligence but has been unable to procure his or her attendance by the court's process." (Evid. Code, 240, subd. (a)(5).) The proponent of the evidence must introduce competent evidence to establish the witness's unavailability. (People v. Cummings (1993) 4 Cal.4th 1233, 1296.) Reasonable diligence "connotes persevering application, untiring efforts in good earnest, efforts of a substantial character." (People v. Cromer (2001) 24 Cal.4th 889, 904.) Relevant considerations include whether the search for the witness was timely begun, the importance of the witness's testimony, and whether leads were competently explored. (Ibid.) The adequacy of the effort depends upon the particular circumstances of the case. (People v. Sanders (1995) 11 Cal.4th 475, 523.) The court must consider the totality of the proponent's efforts to procure the witness's attendance. (Ibid.) In Crawford v. Washington (2004) 541 U.S. 36, 124 S.Ct. 1354, the United States Supreme Court reaffirmed a long-standing exception permitting the admission of "testimonial statements of witnesses absent from trial ... where the declarant is unavailable, and ... the defendant has had a prior opportunity to cross-examine." (Id. at p. 59.) "Evidence Code section 1291 codifies this traditional exception. When the requirements of Evidence Code section 1291 are met, 'admitting former testimony in evidence does not violate a defendant's right of confrontation under the federal Constitution.'" (People v. Wilson (2005) 36 Cal.4th 309, 340, quoting People v. Mayfield (1997) 14 Cal.4th 668, 742.)